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?H^ 



HARVARD UNIVERSITY 

Library of the 

Museum of 

Comparative Zoology 



IVICZ 

TRANSACTIONS OF THE u-tjrxr^ 

SAN DIEGO SOCIETY OF NATURAL HISTORY 

VOLUME 21, 1985-1989 JAN 2 9 199U 

CONTENTS ^^ 

HARVARD 

\. Motility and calcareous parts in extant and fossil Acrothoracica (Crustacea: Cirripedii)N ^ V t-'^'-'^ 
based primarily upon new species burrowing in the deep-sea scleractinian coral 
Enallopsammia. By Mark J. Grygier and William A. Newman, 29 October 1985 1-22 

2. The Sangamon interglacial vertebrate fauna from Rancho la Brisca, Sonora, Mexico. By 

Thomas R. Van Devender, Amadeo M. Rea, and Michael L. Smith, 29 October 1985 23-55 

3. Floral morphology, nectar production, and breeding systems in Dudleya subgenus 
Dudleva (Crassulaceae). By Geoffrey A. Levin and Thomas W. Mulroy, 29 October 

1985..^ 57-70 

4. Fishes living in deepsea thermal vents in the tropical eastern Pacific, with descriptions of 
a new genus and two new species of eelpouts (Zoarcidae). By Richard H. Rosenblatt 

and Daniel M. Cohen, 24 February 1986 71-79 

5. A lectotype for Dinapate wrightii Horn, the giant palm-borer, and description of a new 
species of Dinapate from eastern Mexico (Coleoptera: Bostrichidae). By Kenneth W. 

Cooper, 24 February 1986 81-87 

6. Holocene terrestrial gastropod faunas from Isla Santa Cruz and Isla Floreana, Galapagos: 
evidence for late Holocene declines. By Steven M. Chambers and David W. Steadman, 

5 December 1986 89-110 

7. Callorhinus gilmorei n. sp., (Carnivora: Otariidae) from the San Diego Formation 
(Blancan) and its implications for otariid phylogeny. By Annalisa Berta and Thomas A. 

Demere, 5 December 1986 111-126 

8. Fossil Tanaidacea. By Frederick R. Schram, Jiirgen Sieg, and Eric Malzahn, 5 December 

1986 127-144 

9. Another new forest-dwelling frog (Leptodactylidae: Eleutherodactylus) from the Cockpit 

Country of Jamaica. By Richard 1. Crombie, 5 December 1986 145-153 

10. A new night lizard {Xantusia henshawi) from a sandstone habitat in San Diego County, 
California. By L. Lee Grismer and Mark A. Galvan, 5 December 1986 155-165 

11. The evolution of helodermatid squamates, with description of a new taxon and a 
overview of Varanoidea. By Gregory K. Pregill, Jacques A. Gauthier, and Harry W. 

Greene, 5 December 1986 167-202 

12. Camaenid land snails (Gastropoda: Pulmonata) from the Eocene of southern California 
and their bearing on the history of the American Camaenidae. By Barry Roth. 24 

February 1988 203-220 

13. Pseudotealliocaris palincsari n. sp., a pygocephalomorph from the Pocono Formation, 
Mississippian of Pennsylvania. By Frederick R. Schram, 24 February 1988 221-225 

14. A new species of hagfish, genus Eptatretus (Cyclostomata, Myxinidae), from the Pacific 
Ocean near Valparaiso, Chile, with new data on E. hischoffi and E. polytrema. By 

Robert L. Wisner and Charmion B. McMillan, 24 February 1988 '. 227-244 

15. Two crabs, Xandaros sternbergi (Rathbun, 1926) n. gen., and Icriocarcinus xestos n. 
gen., n. sp., from the late Cretaceous of San Diego County, California, USA, and Baja 
California Norte, Mexico. By Gale A. Bishop, 24 February 1988 245-257 

16. A new abyssal hydrothermal verrucomorphan (Cirripedia; Sessilia): The most primitive 
living sessile barnacle. By William A. Newman and Robert R. Hessler, 15 February 

1989 259-273 

17. New stratigraphic and geographic occurrences of Isognomon (Mollusca: Bivalvia) from 

the Eocene of California and Oregon. By Richard L. Squires, 30 April 1989 275-282 

18. Homology and terminology and higher teleost postcleithral elements. By Michael D. 
Gottfried, 15 October 1989 283-290 

19. Ranges of offshore decapod crustaceans in the eastern Pacific Ocean. By Mary K. 
Wicksten, 15 October 1989 291-316 




S A ^-i 



^^^Rary 



TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 



f^ovzi 



1985 



H^lume 21 Number 1 pp. 1-22 29 October 1985 

^i^i^i^Rsn — — 



Motility and calcareous parts in extant and fossil Acrothoracica 
(Crustacea: Cirripedia), based primarily upon new species burrowing 
in the deep-sea scleractinian coral Enallopsammia 

Mark J. Grygier and William A. Newman* 

Scripps Institution of Oceanography A-002, La Jolla, CA 92093 USA 

Abstract. Four new species of bathyal acrothoracican barnacles of the family Lithoglyptidae are 
described: Lithoglyptes viatrix from Hawaii, L. tectoscrobis and Weltneria ligamenta from Tonga, and 
W. griggi from the Caribbean island of Grenada. All burrow in ahermatypic corals of the genus 
Enallopsammia. Because rostra are very rare in the Acrothoracica, the rostra and calcareous cement 
possessed by at least three of these species are of particular interest. Instead of serving simply to attach 
the barnacle to the burrow wall, they may be modified into a roof (or trail) sealing the apertural slit 
left behind as the barnacle bores across the coral surface. This system is so highly developed in L. 
viatrix that some specimens are truly motile and abandon the older parts of their burrows. Other rostral 
structures in living and fossil acrothoracicans are reviewed, and criteria are given to distinguish rostra 
from calcareous cement. Analogous systems of calcareous structures (cement only) and apertural motility 
in the families Cryptophialidae and Trypetesidae, and in various fossil genera are also discussed; 
apparently none of these acrothoracicans abandon any part of their burrows, although the bulk of the 
mantle may move a considerable distance. A general trend towards loss of the rostrum and calcareous 
cement is evident in extant and fossil Acrothoracica that live in shallow environments, but at different 
stages of reduction the remaining calcareous parts often have been independently modified to protect 
the mantle as the aperture moves to a more favorable position in the substrate. Calcareous parts in 
fossil acrothoracican burrows are not always ichnofossils, but may be true body fossils, a fact which 
has nomenclatural significance. 

Introduction 

The Acrothoracica are burrowing barnacles and most species live in shallow water 
in calcareous substrates such as coral skeletons and mollusk shells (Tomlinson 1 969). 
Their fossil record, almost exclusively in the form of burrows or casts of burrows, 
extends back into the Devonian (Rodriguez and Gutschick 1977). The exterior of an 
adult acrothoracican consists of a sac-like mantle or carapace, and an attachment disc. 
The mantle usually lacks hard parts except for a pair of chitinous opercular bars guarding 
the mantle opening (Newman 1971). The acrothoracicans are further distinguished 
from ordinary barnacles in having all but the first pair of cirri (mouth cirri or maxil- 
lipeds) clustered at the rear end of the thorax. Two suborders and three families are 
generally recognized: Pygophora (Lithoglyptidae, Cryptophialidae) with an anus and 
biramous terminal cirri, and Apygophora (Trypetesidae) without an anus and with 
unbranched cirri. 

This paper concerns four new species of relatively large lithoglyptid acrothoracicans 
that burrow in living and recently dead branches of the bathyal ahermatypic coral 
Enallopsammia. These new species have an unusually deep habitat, and at least 3 of 
them possess a rostral plate, a very rare feature in this order (Newman 1971, 1974). 
Furthermore, at least one of these species, Lithoglyptes viatrix, is capable of a unique 
sort of limited motility. Our efforts to understand the rostrum and its role in motility 



* Direct requests for reprints to WAN. 



in L. viatrix led us to investigate other types of calcareous structures and modes of 
motility in living and fossil Acrothoracica. 

Methods and Materials 

Coral specimens housing the acrothoracicans were obtained from R. W. Grigg 
(Hawaii Institute of Marine Biology), and the National Museum of Natural History 
(USNM) in order to study galls formed on them by ascothoracid crustacean parasites 
of the family Petrarcidae (Grygier 1981, Zibrowius and Grygier, in prep.). Collection 
data accompany each species description given below. Acrothoracicans were detected 
by the characteristic apertures of the burrows and, in some cases, by the presence of 
light-colored streaks extending across the surface of the coral branches (Fig. 2). 

Most of the barnacles had been dried. Those to be dissected were reconditioned 
in a weak trisodium phosphate solution for at least a day, either prior to or after 
extraction. Prior reconditioning gave better results. Animals were extracted from their 
burrows either by dissolution of the coral in dilute HNO3 or by mechanically excising 
the surrounding coral with a hand-held, rotary tool (Moto-tool Model no. 1 , Dremel 
Mfg. Co., Racine, Wisconsin) and diamond wheel. Later dissolutions were not carried 
to completion in order to save as much of the calcareous rostrum in situ as possible. 
Dissected parts and occasionally gut contents were examined in glycerine and glycerine 
jelly mounts. Drawings were done with cameras lucida on Wild M5 and M20 micro- 
scopes. 

Occupied burrows of Lithoglyptes viatrix new species, Australophialus melampygos 
(Bemdt), L. spinatus Tomlinson and Newman (cf. Newman and TomUnson 1974), 
Trypetesa lateralis Tomlinson, and a new species of Trypetesa (Standing and Tomlinson, 
in prep.) were selected for special examination. Some burrows of each were excavated 
with the cutting wheel described above, or with needles and forceps. For L. viatrix, 
dimensions of apertures and exposed "trails" were measured with dividers and a slide 
micrometer. Frontal and sagittal thin sections of L. viatrix burrows were done according 
to Newman et al. (1969), except that blanks were cut on a low-speed saw (Isomet 1 1- 
1 180, Buehler Ltd., Evanston, Illinois) equipped with a diamond cutting wheel. 

Taxonomy 

Class Cirripedia Burmeister, 1834 

Order Acrothoracica Gruvel, 1905 

Family Lithoglyptidae Aurivillius, 1892 

Tomlinson (1969) defined this family on the basis of the tapered burrow apertures, 
lack of a gizzard (gastric mill), possession of caudal appendages in some forms, well- 
developed mouth cirri, and a labrum proportionately comparable in size to the paired 
mouthparts, as in ordinary barnacles. All of these characters are plesiomorphies, as 
shown by comparison with other barnacles. Thus, this family is possibly paraphyletic. 
For the most part, lithoglyptid genera are defined by the presence or absence of caudal 
appendages and the number of terminal cirri (Table 1). 

Variation in opercular bar armament is useful in distinguishing species, but there 
are essentially no other diagnostic characters available. The nonmonotypic genera of 
lithoglyptids must be suspected of paraphyly or polyphyly. But because of the unre- 
solved polychotomies, we are continuing to employ the current, admittedly artificial 
classification for reasons of practicality. 

Lithoglyptes KunviWms, 1892 

Diagnosis. — Lithoglyptids with four pairs of terminal cirri (III-VI) and a pair of 
caudal appendages (Table 1). 




Figure 1. Lithoglyptes viatrix new species a-m, Females, dissected parts; a, b. Lateral and top view of 
opercular region of holotype, carinal end left; c, Labral crest, anterior view, flattened; d, e. Mandibular 
gnathobases, most setae omitted except for insertion sites; f. Mandibular palp; g, h, Maxillular gnathobases, 
setae omitted in h, most omitted in g but insertion sites shown; i. Maxilla, rear view; j. Mouth cirrus (I); k, 
Detail of different mouth cirrus (I), full setation not shown; 1, Typical setation of central part of terminal 
cirrus (IV-VI); m, Protopod of left last cirrus (VI) and caudal appendage; n, o, Complemental males; n, 
Ventral view; o, Ventral view of diflferent specimen. Scale bars 0.1 mm. 



Lithoglyptes viatrix new species 
Figures 1-4 

Diagnosis. —C&XcSirQons cement and a rostrum are present, although the form of 
the rostrum is variable and it may form a roof over an elongate, trench-like burrow. 



Table 1 . Distribution of thoracic appendages among lithoglyptid genera (MC, mouth cirrus or maxilliped; 
TC, terminal cirrus; CA, caudal appendage or furcal ramus). 





I 


II 


Ill 


IV 


V 


VI 


CA 


Weltneria 


MC 


TC 


TC 


TC 


TC 


TC 


CA 


Berndtia 


MC 


TC 


TC 


TC 


TC 


TC 


— 


Lithoglyptes 


MC 


— 


TC 


TC 


TC 


TC 


CA 


Balanodytes 


MC 


— 


TC 


TC 


TC 


TC 


— 


Kochlorine and 
















Kochlorinopsis 


MC 


— 


— 


TC 


TC 


TC 


CA 



The mantle is elongate, and the carinal margin is nearly straight rather than broadly 
curved. The first terminal cirrus (III) has the endopod longer than the exopod. 

Ma/m«/. —Approximately 21 whole and 3 partial females, and 2 males, in En- 
allopsammia amphelioides (Alcock) [Cairns (1982) considers this a synonym of £". 
rostrata (Pourtales)] from 4 localities in the Hawaiian Islands (Table 2). All had been 
air-dried. Chamberlain's specimens from Oahu and Grigg's from Kaula Rock are chosen 
as type lots because they include most of the specimens examined. The dissected 
holotype from Kaula Rock (USNM 210849) and 5 paratypes from both localities 
(USNM 210850) are deposited in the National Museum of Natural History. Other 
paratypes are deposited in the British Museum (Natural History), Zoology and Pa- 
laeontology Departments (Reg. nos. 1984. 140-144 and T8 14, respectively), the Bemice 
P. Bishop Museum, Honolulu (Cat. No. B510), the Institute for Paleontology, Uni- 
versity of Vienna (IPUW-2523), the San Diego Natural History Museum, San Francisco 
State University, and the authors' collections. 

Etymology. —From Latin viator (a traveler) with feminine suffix, referring to female 
motility. 

Description. —VQxmXts: Operculum fusiform (Fig. la, b), that of holotype 2.1 mm 
long, 0.7 mm wide, wider toward carinal than rostral end, slightly smaller than burrow 
aperture. Sharp denticles interspersed with minute hairs along lateral edges of bars, 
faces with scattered papillae; closely-spaced, ffat-topped papillae along medial edges. 
Comb collar between carinal halves of opercular bars. 

Mantle long (5 specimens 4.3-7.5 mm), tapered, often bent nearly at right angle 
just below operculum (Fig. 4d-f); well-muscled, with small bifid or trifid spines. Very 
small attachment knob below operculum rostrally. Pair of soft lobes below carinal end 
of opercular bars, covered with short setae and bearing short spines mostly along free 
edge (Fig. la). 

Labral crest with denticles, short setae on surface (Fig. 1 c). Mandibles serrate with 
2-4 teeth (Fig. Id, e); inferior angle with 6-12 sharp spines along distal edge; distal 
part of blade with short hairs and setae. Mandibular palps tapered, twice as long as 
broad, covered with fine hairs, row of setae along posterodistal edge (Fig. 1 f). Superior 
angle of maxillule (Fig. 1 g, h) with 2-3 large spines, 2 smaller ones, then a notch with 
a few small spines; inferior half of distal margin with numerous medium-sized spines; 
faces distally setose with proximal field of cuticular ctenae along superior margin. 
Maxillae triangular, as high as broad, with setae on anterior face and both margins, 
denser and longer on medial edge (Fig. li). 

Mouth cirri with long, arcuate coxae; bases a third as long as coxae, twice as long 
as wide (Fig. Ij, k). Anterior ramus 5 -segmented (fifth article often partly or wholly 
fused to fourth), posterior one 2-4 segmented. Basis and rami armed mostly posteriorly 
with plumose setae, 2 rows on anterior ramus. 

Four pairs of terminal cirri, first shortest, second intermediate, third and fourth 
longest. Posterior ramus of each (endopod) generally a few articles longer than anterior 
ramus (exopod). Among 4 specimens examined, segmental counts rarely varied by 
more than 3. A typical segmental count is as follows (?, repeated counts not equal; +, 
part of ramus broken off and not counted): 



Ill 



IV 



VI 



Right 


Exopod 


20 


33 


40 


46 




Endopod 


28 


33 + 


42 


52 


Left 


Exopod 


21 


34 


44 


43? 




Endopod 


28 


39 


48 


49 + 



Medial setae on coxa and basis. Five setae on anterior side of each cirral article (Fig. 
11): 3 distal (long, medium long, very short), 2 unequal short ones at midlength, at each 
position the most lateral seta longest. Long distal seta on posterior margin of each 
article in first pair (III), every 2-3 articles in others; single short seta at longer intervals, 
and then usually coincident with a long one. 

Caudal appendages 2-segmented, not including basal pedestal, reaching to mid- 
length of protopod of last cirrus (Fig. 1 m); second article longer than first or pedestal. 
Tuft of about 7 plumose, distal setae on second article, 2-3 on first. 

Males: Attached to mantle or to edge of rostrum of 2 different females. One with 
pear-shaped body 0.44 mm long, 0.32 mm high (Fig. In). Cuticle at narrow end with 
circular striations. Pair of antennules rising directly from body at lower comer of thick 
end. Other male V-shaped, 0.5 mm wide, larger arm 0.6 mm long; antennules rising 
from long, tapered, antero ventral protrusion (Fig. lo). Antennules in both specimens 
4-segmented, first article short, second elongate, third slightly flared distally for at- 
tachment, fourth a small appendix of the third. 

Burrows. —Corals with burrows were of varying states (Table 2). A few were alive 
when collected, as shown by the brown remains of dried tissue. Most were recently 
dead, lacking tissue, but still white and little eroded. One, with an extensively pitted 
surface and dark deposits of mineral precipitates, had clearly been dead for some time. 
The majority of the burrows occur on the surface of the coral opposite that bearing the 
calices. 

Burrow apertures are key-hole shaped, 0.8-2.5 mm long, and 0.2-1.0 mm wide 
(Fig. 2). The carinal end is rounded, while the rostral end tapers to a constriction formed 
by a protruding shelf of cement and the end of the rostrum. There is often a light- 



Table 2. Enallopsammia amphelioides (Alcock) [? = E. rostrata (Pourtales) of the Atlantic; cf. Cairns 1 982] 
branches from Hawaii containing burrows of Lithoglyptes viatrix new species. Coral condition when 
collected: 1 , alive, brown; 2, recently dead, white, costae rough; 3, white, costae smooth; 4, white, costae 
obliterated, or minor pitting; 5, long dead, grey, considerable pitting. For burrow number, the first entry 
is the number of burrows unambiguously assignable to L. viatrix, the entry in parentheses is the number 
of other possible acrothoracican burrows (usually very small) of unconfirmed origin. 



Collection 



Coral Burrow 
condition number 



Burrow condition 



R. Grigg, Sango III, Kaena Pt., Oahu, 9-VIII-1970, 21°35'N, 
158°24-25'W, 440-490 m 

R. Grigg, Sango III, Kaena Pt., Oahu, 9-VIII-1970, 
2I*'35.8'N, 158°24.3-24.9'W, 470-475 m 

R. Grigg, Kaena Pt., Oahu, 19-XII-1973, 378 m 

R. Grigg, Sango XIII, Kaula Rock, 30-VIII-1971, 21°43.0- 
43.8'N, 160°36.5-37.5'W, 386-500 m 

T. Chamberlain, Hawaii (Grigg, personal communication; 
Makapuu Pt., Oahu, -400 m, 1967) 

R. Grigg, Sango XIII, Brooks Banks, 23-VIII-1971, 24°0.9'N, 
166°42.5'W, 384-432 m 



1 

1 

3 
4 
3 



2 
4 
3 
4 
4 
1 



1 Empty 

5 Empty, collapsed 

5 Empty, except 1 with 

an opercular bar 

2 Empty 

16 5 occupied 

5 Empty 

24 (1) 1 occupied 

25(1) 4 occupied 

22 (6) 1 1 occupied 



0(1) 
8 
1 
13 
7 
1 



Empty 

Empty 

Empty 

1 occupied 

Empty 

Occupied 




Figure 2. Burrows and trails of Lithoglyptes viatrix new species on Enallopsammia amphelioides. a, Typical 
burrows with short trails (most examples no longer than this); b. Burrow with long trail; c, Two long trails, 
the younger one having partly incised the older, arrow pointing to aperture of burrow of unknown origin 
(possibly acrothoracican or polychaete); d, Two long trails, younger barnacle having cut completely through 
older burrow and trail. Apertures between 1.25 and 2.0 mm long. 



colored streak or trail formed by the cement and rostrum extending across the coral 
surface. The burrows themselves vary from a typical acrothoracican pit to an elongate 
trench roofed over by such a trail. 

Figure 3 shows the distribution of trail lengths on several pieces of coral and 
compares them with the size of the corresponding burrow apertures. There is no evident 
correlation. Most trails are only a few mm long (Fig. 2a), but some are as long as 2 
cm, and a number of barnacles, including all those burrowing in calices, seem to have 
no trails at all. The exposed surface of a trail has more or less parallel sides as far apart 
as the aperture width, but the trail narrows at its extremity. It is generally flush with 
the coral surface, with arcuate or chevron-shaped, transverse ridges concave toward 
the aperture (Fig. 2b, d). These ridges are growth lines; they penetrate sharply into the 
trail, then turn away from the aperture. 

Although there are some exceptions, most trails are oriented more or less longi- 
tudinally on the coral and, thus, are generally parallel to each other. In some cases one 
trail partly overlaps another, or begins in the middle of another (Fig. 2c); the original 
trail in such cases is the one partly excised by the other. A burrow aperture may also 
cut into an established trail (Fig. 2d), but no trails were observed to cut all the way 
across another. A burrow can be straight, or it can twist and turn vagariously in three 
dimensions. It is usually curved at least a little (Fig. 2c, d) and may even "bank" as it 
bends around an obstruction like a calice or pit. Trails, at least their older portions, 
are occasionally overgrown by the host coral. In cross-section or at a break in the coral, 
burrow roof material can be seen under a layer of coral skeleton. In other cases, the 
burrow roof is collapsed, leaving a deep trench in the coral; no collapsed burrow was 
occupied by a barnacle. In one piece of coral, the trails were recessed into trenches but 
not overgrown. Two of these recessed trials "sideswiped" each other at different levels 
below the coral surface. 



10- 



E ' 

E . 






CD 



r^ 4 
CO 



2- 









• • • 



• • 



•• • * 






— ^ 



3 



Aperture Length (mm) 



Figure 3. Relationship of aperture length to trail length for the type lots of Lithoglyptes viatrix new species 
burrowing in Enallopsammia amphelioides. Only trails whose extremities are clearly visible are included; 
larger dots are superimposed records. 



A typical elongate, horizontal trail is composed of a rostral plate and the cement 
holding it in place. This compound structure overlies a horizontal burrow with an 
elliptical cross-section higher than wide (Fig. 4a, b). The convex top of the rostrum is 
not exposed because of overlying cement. In the rostrum's thickest, central part, several 
upwardly convex layers corresponding to growth increments are visible. A thin layer 
of cement or cemented tailings lines the sides and bottom of the burrow. 

The rostrum is bounded by a chitinous membrane which remains after acid dis- 
solution. This chitinous structure retains the shape of the rostrum and exhibits obvious 
growth lines. It has a large open end attached to the edges of the extensive, calcium 
carbonate-secreting region on the rostral side of the barnacle's mantle (Fig. 4c-f). 

The cross-section of the trail (Fig. 4b) also shows how the rostrum is held within 
the top of a parallel-sided trench above the burrow lumen by an organo-calcareous 
cement (white by reflected light, orange-brown by transmitted) that adheres to the coral 
and to the chitinous lining of the upper lining of the rostrum. This cement, which may 
not be entirely of secretory origin (Kamens 1981), must be laid down by a different 
mantle region than the rostrum-secreting area, likely on the rostral side of the short 
neck below the opercular bars. 

When subjected to acid, the cement dissolves much more quickly than the rostrum, 
at least in part because of the thin chitinous membrane separating the two. When the 
thin layer of cement covering the upper side of the rostrum is fully dissolved, this 
membrane is evident, and the two calcareous structures are quite distinct. The cement 
is a very bright, opaque white, whereas the rostrum is lustrous and translucent, but 
uncolored, and appears much less bright. 

Comparison. —The 4 pairs of terminal cirri and the caudal appendages are diag- 
nostic o{ Lithoglyptes (Tomlinson 1969). Most of the species in this genus have prom- 
inent hooks on the operculum and, therefore, can be readily distinguished from L. 
viatrix. Those that do not have hooks are L. indicus Aurivillius, L. mitis Tomlinson, 



8 




Figure 4. Lithoglyptes viatrix new species, burrow structure and rostral growth, a, Cross-section of burrow 
(coral surface hatched, calcareous cement stippled, rostrum with growth lines); b. Detail of burrow roof in 
a. c-f, Adult females dissolved out of coral substrate; remaining calcareous part of rostrum stippled, c, 
Primitive rostral growth, new layers added away from aperture (precise orientation in coral unclear and 
operculum lost); d. Advanced rostral growth, new layers added at apertural end, resulting in bodily translation; 
e, Rostral and side views of specimen that initially grew as in d, but stopped moving and grew in place; f. 
Rostral and side views of specimen that grew like older stage of e, but was obstructed away from the aperture 
by an overgrown thoracican barnacle. Scale bars 1 mm except 0. 1 mm in b. 



and some specimens of L. habei (Tomlinson). The last two have bifid rather than simple 
opercular spines and teeth. Lithoglyptes indicus has many small spines rather than 
scattered papillae over the faces of the opercular bars. It also has elongate rather than 
short distal articles on the caudal appendages, and the rostral side of the mantle is at 



an angle to the operculum rather than being parallel. The significance of a calcareous 
rostrum, not previously known to occur in this genus, is considered in the Discussion. 
Associated fauna. —Some empty burrows are secondarily inhabited by a tanaid. 
One barnacle-occupied burrow had its aperture covered by a sponge. About a dozen 
very small burrows were interspersed among those of L. viatrix (Table 2; Fig. 2c). Their 
apertures are elliptical, typically with a constriction in the middle. Perhaps they were 
formed by young L. viatrix or by spionid polychaetes, but because none was occupied 
this cannot be demonstrated. A number of corals had old, empty galls of an as yet 
undiscovered ascothoracid crustacean, presumably a Petrarca species; large, round, po- 
rous galls are typical of that genus, which has been found infesting Enallopsammia in 
the Atlantic, Pacific and Indian Oceans (Lopez 1974, Zibrowius 1980, Grygier 1981 
and in press, Zibrowius and Grygier, in prep.). The corals were often fouled with 
bryozoans, foraminiferans, gammaridean amphipods, and juvenile balanomorph bar- 
nacles [Chionelasmus darwini (Pilsbry); Newman, in prep.]. 

Lithoglyptes tectoscrobis new species 
Figure 5 

Diagnosis. —The calcareous cement and rostrum form a roof over an elongate 
trench-like burrow. The mantle is elongate with a tubular distal end, and the carinal 
margin is broadly rounded. The first terminal cirrus (III) has an exopod longer than 
the endopod. 

Material. — Holotype female (USNM 2 10848) in Enallopsammia amphelioides (=? 
E. rostrata; see Cairns 1982) collected by Committee for the Coordination of Joint 
Prospecting for Mineral Resources in South Pacific Offshore Areas (CCOP/SOPAC), 
Tonga Offshore Survey Stat. 78(2)-5, 12-XI-1978, 19°25.0'S, 174°13.4'W, 250-290 m; 
forwarded by R. W. Grigg. 

Etymology. —From Latin tectum (rooO and scrobis (trench), referring to the roofed 
burrow. 

Description. —Mantle 5.7 mm long, aside from a narrow, 1 .0 mm long tube at rear; 
semicircular in side view, 1.7 mm across at midlength; operculum parallel to rostral 
side of mantle (Fig. 5a, b). Operculum 1 .9 mm long, 0.7 mm across, carinal end rounded, 
rostral end distinctly tapered (Fig. 5c, d). Lateral edges with irregular denticles and 
short, fine hairs; faces with numerous, regularly spaced papillae interspersed among 
and dotted with innumerable granules; medial edges with no special armament, but 
papillae a little more abundant there. Mantle set with simple, bifid, or trifid spinules, 
proximal part also with fine hairs, larger and more abundant toward carinal end. Comb 
collar between opercular bars. Pair of small lobes below carinal end of operculum, 
thickly set with hairs and bearing about 15 strong teeth each. Long setae on inner 
mantle wall near operculum, denser toward carinal end. Attachment knob inconspic- 
uous, focus of radial array of mantle muscles; prominent longitudinal muscles also 
present. Rostral surface largely an oval, yellow, glandular region. Tube rising from near 
back end of this tissue, with proximal half hollow and distal half plugged with several 
layers of chitin (Fig. 5e). 

Row of conical denticles along crest of labrum (Fig. 5f). Mandibles with 3 narrow 
teeth separated by deep notches (Fig. 5g, h); inferior angle with 7-8 small teeth and 
large, trifid tooth at very tip; setation as in L. viatrix. Mandibular palps tall, narrow 
triangles with posterior row of setae (Fig. 5i). Maxillules as in L. viatrix, but spines 
near inferior angle smaller than rest (Fig. 5j). Maxillae a little longer than broad, broadly 
pointed, with row of setae along distal margins and other setae scattered over distal 
half of anterior face (Fig. 5k). 

Bases of mouth cirri half as long as coxae; anterior ramus 5-segmented, posterior 
one 3-4-segmented (Fig. 51). Setation similar to L. viatrix. 

Four pairs of terminal cirri. First pair shortest, second next shortest, last 2 pairs 
equally long. Segmental count of exopod larger than endopod in first pair, reverse in 



10 




Figure 5. Lithoglyptes tectoscrobis new species, holotype female, a, b. Lateral and rostral views of whole 
animal, shaded region glandular, chitinous rostral lining present (calcareous part dissolved away); c, d. 
Operculum, top and side views, papillae and granules shown only for part of one valve; e. Posterior mantle 
tube; f, Labral crest, flattened out; g, h. Mandibular gnathobases, only insertion sites shown of many setae; 
i, Mandibular palp; j, Maxillular gnathobase; k. Maxilla, front view; 1, Mouth cirri (I), setae omitted; m, 
Protopod of last cirrus (VI) and caudal appendage. Scale bars 0. 1 mm except 1 mm in a and b. 



second pair, almost equal in third and fourth pairs. Setation as in L. viatrix. Segmental 
counts as follows: 







III 


IV 


V 


VI 


Right 


Exopod 


37 


42 


55 


55 




Endopod 


28 


50 


55 


57 


Left 


Exopod 


36 


44 


51 


55 




Endopod 


26 


50 


54 


56 



11 

Caudal appendages 2-segmented, on pedestal, reaching to midlength of protopod 
of last cirrus (Fig. 5m). Basal article little longer than pedestal, with 2 posterior, sub- 
terminal setae; distal article little longer than basal one, with 6 terminal setae. 

Eggs. —Oblong mass of about 1 200 yellow, oval (0. 1 8 x 0. 1 3 mm) eggs in mantle 
cavity, number estimated volumetrically. 

Gut contents. —Apparently of detrital origin, including sponge spicules, yellow- 
green globules, a few possible crustacean parts, and large quantities of a granular, 
amorphous substance. 

^wrrow. —Aperture 1.95 mm long, 0.70 mm wide, a tapered oval narrower at 
rostral end. Trail 3.9 mm long, identical in external appearance to those of L. viatrix. 
Aside from proximal and distal ends, trial overgrown by coral skeleton. Barnacle 
occupying all except innermost part of burrow, where mantle tube continues up and 
out toward coral surface. 

Comparison. —The only acrothoracican comparable to L. tectoscrohis is L. viatrix, 
with which it shares a major specialization— the rostrum employed as a burrow roof 
{see Discussion). It differs from L. viatrix in having a tube at the end of the mantle, 
even less opercular armament, smaller lobes below the carinal end of the operculum, 
and a longer exopod than endopod on the first terminal cirrus. This last character is 
highly unusual; all other species of Lithoglyptes, Weltneria, and Berndtia have a longer 
endopod than exopod on the homologous limb (III; second terminal cirrus in the last 
2 genera) (Tomlinson 1969), although limb II, when present, may have a longer exopod 
(cf. W. ligamenta new species below). 

Weltneria Bemdt, 1 907 

Diagnosis. — Lithoglyptids with 5 pairs of terminal cirri (II-VI) and a pair of caudal 
appendages (Table 1). 

Weltneria ligamenta new species 
Figure 6 

Diagnosis. —Opercular bars are connected by a conspicuous, bipartite "ligament." 
No setae or marginal teeth are present on opercular bars. 

Material. — Holotype female (USNM 210846) from same collection as lithoglyptes 
tectoscrohis new species. 

Etymology. —From Latin ligamentum (a band or tie), referring to the remarkably 
well-developed ligament connecting the opercular bars. 

Description. —Typical, sac-like mantle. Operculum 2.7 mm long, 0.6 mm across 
at widest point (about 'Z? of way from rostral end); bars connected there by pair of 
elevated, oval longitudinally aligned, medially fused "ligaments" one-fourth as long as 
bars (Fig. 6a, b). Opercular armament feeble, numerous small papillae scattered over 
faces and margins, no apical hooks. Carinal half of medial margins crenulate, paralleled 
internally by comb collar. Mantle wall below operculum scaly, with small papillae; 
heavier spines along carinal edge. 

BuUate labrum with curved setae on each side, crest with evenly spaced denticles 
(Fig. 6c). One mandible serrate, with 4 teeth, other with 5 (Fig. 6d, e); inferior angle 
with 2-4 heavy spines; faces sparsely covered with setae, inferior margin with long, 
fine hairs. Triangular mandibular palps flanking labrum, about twice as long as wide, 
with setae along posterior edge, few distal setae along edge (Fig. 6d). Maxillules with 
strong spine at superior comer, about 10 lesser spines in 3 loose clusters along cutting 
edge; faces with few strong, distal setae, distal part of inferior margin with many long, 
fine setae (Fig. 6f, g). Maxillae joined basally, longer than broad with blunt tips; abundant 
setae along distal margin and down anterior face (Fig. 6h). 

One mouth cirrus lost in dissection. Other well-developed, with long, curved coxa 
(possibly secondarily jointed at about '/3 length), short setose basis (Fig. 6i); anterior 
ramus 6-segmented, each article well-armed with setae; posterior ramus 3-segmented, 
first article longest, all setose (Fig. 6j). 





II 


III 


IV 


V 


VI 


Exopod 


21 


31 


43 


51 


52 + 


Endopod 


14 


38 


49 


53 + 


. 54 + 


Exopod 


22 


32 


41 + 


48 


52 


Endopod 


15 


39 


47 


54 


57 + 



12 



Five pairs of terminal cirri. First shorter than others, exopod much longer than 
endopod. Other cirri progressively longer, exopods slightly shorter than endopods. 
Setation as in L. viatrix (Fig. 6k). Segmental counts ± 1 (2 counts) as follows: 



Right 
Left 



Caudal appendages biarticulate, half as long as coxa of last cirrus, each article with 
heavy terminal setation (Fig. 6 1 ). 

Burrow. —Coral broken at burrow and portion bearing rostral half of burrow lost, 
so existence of calcareous rostrum un verifiable; carinal end of aperture round. 

Comparison. — Weltneria ligamenta fits the diagnosis of the genus given by Tom- 
linson (1969) in having 5 pairs of terminal cirri and caudal appendages. It differs from 
the 6 previously described species in the unique development of an opercular "ligament" 
and in the lack of setae and marginal teeth on the operculum. 

Weltneria griggi new species 
Figure 7 

Diagnosis. —A calcareous rostrum is present. The opercular bars have abundant 
long setae, simple spines along the lateral edges, papillae along the medial edges, and 
more complex spines laterally on the faces. 

Material. -HoXoXy^Q female (USNM 210847), dried. Collected 22-1-1972, R/V 
Oregon Sta. 11722, 3r46'N, 79°15'W (vicinity of Blake Plateau), 402 m, in Enallo- 
psammia rostrata. 

Etymology. —'H^mcd for R. W. Grigg (Hawaii Institute of Marine Biology), in 
appreciation for amassing the coral collections in which most of the material described 
herein was discovered. 

Description. —M?in\\Q a simple sac 5.8 x 3.6 mm (Fig. 7a). Longitudinal muscu- 
lature clearly evident. Small papillae and bifid or trifid spinules scattered about (Fig. 
7b), and sub-opercular region with hairs, more extensive along carinal side. Rostrally 
upswept opercular bars 2.5 mm long, each 0.43 mm across just rostrad of midlength 
(Fig. 7c, d). Rostral half generally wider than carinal half, but tips equally sharp. Long 
setae on faces and along lateral edge, short setae along medial edge. Sharp spines along 
lateral edge, blunt papillae along medial edge. Smaller papillae on medial half of face; 
tall, simple or bifid spines on lateral half Comb collar present. Thorax bent into the 
shape of an S within mantle (Fig. 7e). 

Bullate labrum with cuticular ctenae and lateral setae; crest with row of blunt 
denticles (Fig. 71). Mandibles with 3 teeth, inferior angle blunt or divided into several 
small teeth, setation heavy, but absent on superior tooth (Fig. 7g, h); mandibular palps 
narrow with many setae distally and posteriorly (Fig. 7g). Maxillules with 2 large and 
2 small superior teeth, a gap, and about 10 inferior teeth; setation typical (Fig. 7i, j). 
Maxillae broad, triangular, with row of long, medial setae, as well as shorter anterior 
and lateral setae (Fig. 7k). 

Mouth cirri with long, slightly arched coxae and short, non-setose bases (Fig. 71). 
Anterior ramus with 4 segments in one, 3 in other, posterior with 5 segments in both, 
and setation essentially the same in both despite different segment number (Fig. 7m). 

Five pairs of terminal cirri. Cirral articles armed as in L. viatrix. First cirrus 
shortest, second next longer, other 3 pairs about same length, exopods apparently shorter 
than endopods, but not confirmed in all limbs (many broken off); segmental counts as 
follows: 



13 



Right 
Left 



Exopod 
Endopod 
Exopod 
Endopod 



II 

? 
? 
? 

20 



III 

30 
? 

31 

36 



IV 

9 

41 
? 

43 



38 

46 
? 

45 



VI 

39 
48 
47 
46 




Figure 6. Weltneria ligamenta new species, holotype female, a, b. Lateral and top views of operculum, 
ligament shaded (arrow); c, Labrum and mandibular palps, rear view; d, e. Mandibular gnathobases, d with 
palp, only some setae shown in full, setae omitted from e; f, g, Maxillular gnathobases, setae not shown in 
full in f, omitted in g; h, Maxillae, rear view; i. Mouth cirrus (I), arrow pointing to possible secondary joint 
in coxa (or break); j, Rami of i; k, Typical setation of middle part of terminal cirrus (III-VI); 1, Caudal 
appendage (removed from pedestal). Scale bars 0. 1 mm except 1 mm in a and b. 



14 




Figure 7. Weltneria griggi new species, holotype female, a, Whole animal, lateral view, cuticle of rostrum 
shown, remaining part of rostrum stippled; b, Types of mantle spines; c, d. Lateral and top view of an 
opercular valve; e. Cutaway view of mantle, showing folded thorax and terminal cirri; f, Labrum, side view; 
g, Mandibular gnathobase and mandibular palp; h, Inferior angle of other mandible; i, j, Maxillular gnatho- 
bases, setae omitted in j; k. Maxilla; 1, Mouth cirrus (I), some muscles shown; m. Rami of 1, most setae only 
shown as bases; n, Protopod of last terminal cirrus (VI) and caudal appendage; o, Detail of caudal appendage 
in n. Scale bars 0. 1 mm except 1 mm in a and e. 



Caudal appendages 2-segmented, less than half as long as coxa of last cirrus (Fig. 7n, 
o); articles equal, first with 2-3 anterior setae, second with 1 short, several long, plumose 
setae. 

Burrow.— Apenure 2.5 x 1.2 mm; 0.65 mm of trail visible on coral surface. 

Comparison. —The 5 pairs of terminal cirri and caudal appendages assign this 
specimen to Weltneria (Tomlinson 1969). Like W. hessleri Ne-wman, and W. exargilla 



15 

Newman, W. griggi lives in deep water and has a calcareous rostrum. However, this 
plate has a different shape and orientation, being transitional towards those of Litho- 
glyptes viatrix and L. tectoscrobis {see Discussion). The opercular armament differs 
from both of the earlier rostrate species of Weltneria, and there are fewer articles on 
the rami of the mouth cirri. Weltneria griggi differs from W. spinosa Bemdt in lacking 
a pair of opercular hooks, and from that species and the remaining three, W. hirsuta 
(Tomlinson), W. reticulata Tomlinson, and W. aapta Tomlinson, in having only simple, 
not bifid, lateral opercular spines. Unlike W. ligamenta, W. griggi has no "ligament" 
joining its much more heavily armed opercular bars. 

Discussion 
The Rostrum and Motility in Lithoglyptes viatrix 

Weltneria hessleri and W. exargilla. North Atlantic abyssal inhabitants of calcar- 
eous and muddy bottoms, respectively, were the first acrothoracicans found to have a 
calcareous rostrum (Newman 1971, 1974). Their rostrum is a triangular plate, much 
like that of scalpelloid barnacles, but it is cemented to the burrow wall (Fig. 8, la). The 
umbo is apical and projects freely; successive growth increments are added at the bottom 
edge as the animal burrows deeper into the substrate. Turquier (1978) disputed that 
this plate is homologous with the scalpelloid rostrum because he inferred that its 
position was not "rostral." Newman (1982) refuted the objection; the plate is rostral 
in form and position, but its homology with the rostrum of ordinary barnacles can, 
without additional evidence, always be doubted. In any event, it is a structural feature 
of these acrothoracicans, distinct from secreted, calcified cement. 

Newman (1974) pointed out that the so-called cement discs, composed of uncal- 
cified cement and exuvia, and which anchor most acrothoracicans within their burrows, 
sometimes have a rostrum-like appearance {see examples in Tomlinson 1969). It is not 
possible to tell from wholly decalcified specimens (the usual technique for extracting 
the barnacles) whether a rostrum or just a cement disc was involved. However, there 
are two ways to tell the difference in untreated specimens. If two distinct sorts of 
material are exposed, either in section or by partial dissolution, as in L. viatrix, it is 
likely that one is the rostrum and the other the cement holding it in place. We urge 
future investigators to examine at least some burrows mechanically before acid dis- 
solution in order to verify the presence or absence of a rostrum. For example, we so 
treated Lithoglyptes spinatus and found no rostrum, just cement. The calcareous shield 
in the burrows o^ Lithoglyptes indicus is of calcified cement only and is not a rostrum, 
since no cuticular lining or other organic trace is left after dissolution in acid (Auri villius 
1894). 

The burrows, and especially the rostra, of L. viatrix are extremely variable. Some- 
times the animal digs into the coral substrate while producing a rostrum with an apical 
umbo near the operculum, in the same manner as Newman's Weltneria species (Fig. 
4c). At the other extreme, the burrow and rostrum develop in a horizontal direction, 
with the umbo at the end farthest from the operculum (Fig. 4d). New growth increments 
are added at the opercular end and cemented laterally to the burrow walls, forming the 
longer of the so-called trails described in detail above. The horizontal burrow is ap- 
parently excavated by the carinal end of the mantle as newly secreted rostrum and 
cement advance the animal against the carinal wall of the aperture. The spines on the 
lobes below the operculum probably play an important role in the abrasion process, 
likely combined with chemical action (Kamens 1981). 

Most L. viatrix are intermediate between these two extremes (Fig. 4e, in having 
trails about as long as the burrow apertures. The rostra in such individuals have a 
variety of forms, revealed upon dissolution, that reflect changes in proportion of the 
vertical and longitudinal components in growth (growth referring to the addition of 
increments to the rostrum relative to the surface of the coral). One can assume that 
the cues regulating this behavior involve orientation to currents, avoidance of burial, 
interference from neighboring barnacles, obstructions to growth (such as balanomorph 



16 






17 

barnacles and coral calices), etc., but the relative importance of such cues cannot be 
estimated without experimental evidence. 

In cases where burrow excavation proceeds horizontally, the animal does not 
remain attached at the origin of the burrow, passively growing to occupy newly available 
space. Rather, the animal is carried along as rostral growth continues, and as a whole 
abandons the older part of the burrow (Figs. 4d, e; 8, Ic). It may eventually move 
farther than its body length. If the old burrow were not roofed by the rostrum, the 
barnacle would be vulnerable to attack from the rear; apparently because of the trail 
no foreign organisms were ever found in the evacuated part of a barnacle-occupied 
burrow. Sometimes secondary inhabitants (tanaids, etc.) live in empty burrows. It is 
unlikely that one burrow successfully crosses another because accidental intrusion into 
an abandoned burrow invites attacks from predators. 

Homologues and Analogues in Extant Forms 

Lithoglyptes tectoscrobis has an elongate, horizontal rostrum like some specimens 
of L. viatrix. Since only one specimen was available to us, we cannot say whether this 
is typical, or if this species shows the same range of growth forms as L. viatrix. Weltneria 
griggi has a rostrum that exhibits both vertical and horizontal growth (Fig. 8, lb). Again, 
the range of its behavior is not known. Weltneria hessleri and W. exargilla, the only 
previously known deep-sea lithoglyptid acrothoracicans, both have more conventional, 
vertically oriented rostra. One begins to suspect that most large, deep-water acrothoraci- 
cans have rostra. Weltneria ligamenta may have had one, too, but unfortunately the 
part of the coral that would have borne it was unavailable for examination. In all the 
cases so far mentioned, it is certain that the rostra are homologous. 

Noll (1875), in his drawings of Kochlorine hamata from Cadiz, Spain, shows 
grooves in the gastropod shell substrate (Haliotis tuberculata Linne) leading to burrow 
apertures. He attributed the grooves to abortive attempts of the newly settled cyprid 
larvae to begin excavation. Where known, however, the larvae do not begin to burrow 
until after attachment and metamorphosis (Batham and Tomlinson 1965, Turquier 
1 970). Therefore, the floor of these grooves is more likely the cement layer over a partly 
horizontal rostrum, or the rostrum itself We have as yet been unable to obtain spec- 
imens of this species in situ to confirm this suspicion. 

All of the foregoing examples have been from the primitive family Lithoglyptidae. 
This is not surprising. If the rostrum is a holdover from a thoracican barnacle ancestor, 
its presence is a plesiomorphic condition liable to be maintained in one or more lines 
of descent. 

An analogue to the situation in L. viatrix is provided by Australophialus melam- 
pygos, a representative of the more plesiomorphic genus of the otherwise advanced 
Cryptophialidae, living in shells such as that of the mussel Perna canaliculus Gmelin 
from New Zealand. Batham and Tomlinson (1965) photographed burrow apertures 
that had a white streak extending from each of them, which they interpreted as accu- 
mulations of tailings (sensu Darwin 1854; see below). In reexamining this species, we 
discovered that the white streak is a cement burrow roof, as in L. viatrix, but that there 
is no rostrum and the mantle is not attached to the roof (Fig. 8, lib). There is a normal 
cement disc at the end of the burrow holding the barnacle in place. As the aperture 
moves, apparently to even out the inter-apertural distances, the mantle expands in the 
carinal direction, no part of the burrow being evacuated. Some burrowing takes place 
around the edges of the cement disc, which is eventually replaced by a larger, deeper 
one. Tomlinson (1969) shows such a series of cement discs in this species and also in 
A. utinomii Tomlinson (Fig. 8, Ila). 

Other living analogues are Trypetesa lampas (Hancock) of the North Atlantic, 
described by Darwin (1854) as Alcippe lampas, and by an undescribed species of 
Trypetesa from North Carolina (Standing and Tomlinson, in prep.) (Fig. 8, III). The 
latter settles on the lip of gastropod mollusk shells inhabited by hermit crabs. It then 
burrows toward the interior, sometimes reorienting 1 80° before doing so. In many cases 
the burrow aperture is a normal ellipse, but often there is an additional, narrow, curved 



18 

slit from the rostral end. This slit may extend a short distance in T. lampas, or several 
times the length of the opercular part of the aperture in the new species of Trypetesa 
and in some specimens of T. lateralis. The edges of the slit in all but the last species 
are formed of a secreted white substance reminiscent of the cement in L. viatrix (Fig. 
8, III). Darwin (1854), contrary to Hancock (1849), considered the calcareous rims to 
be inorganic accumulations, rather than secretions of the animal. Kamens (1981) stud- 
ied the burrows of T. lampas with SEM and chemical tests and showed that the 
calcareous part of these deposits probably originates from the inhabited gastropod shell 
as a breakdown product, not as a precipitation of dissolved CaCOj, but as redeposited 
calcareous spherules. He could not determine the source of the organic matrix, but 
most acrothoracicans are capable of secreting an uncalcified, organic cement, so we 
think it likely that such a substance serves as the organic matrix here. The calcified 
cement of other acrothoracicans, including L. viatrix, may have a similar compound 
origin. We did not observe lines of deposition noted by Darwin (1854) and Kamens 
(1981), but the exposed surfaces were generally worn flush with the surface of the snail 
shell and, therefore, the lines of deposition may have been abraded away by the actions 
of the hermit crab. 

Trypetesa is weakly attached within the burrow. In T. lampas this is accomplished 
by a disc-like mantle expansion (Fig. 8, Ilia), and very weakly if at all in the undescribed 
species by the tip of a long, prow-shaped mantle projection (peduncular rudiment) (Fig. 
8, Illb). The slit itself is closed by a thin, tough, membranous material in both species, 
and there is no rostrum. 

Fossil Acrothoracica with Roofed Burrows 

Zapfe (1936) described and provided photographs of Miocene acrothoracican bur- 
rows in the gastropods Pyrula cornuta Agassiz (apertural view of shell and an enlarge- 
ment of a region of same) and Fasciolaria tarbelliana Grateloup (apertural view of 
shell). The same two photographs of Pyrula were published by Hantzschel (1962:W23 1; 
fig. 144, la and b, and 1975:35; fig. 83, 2c and d) as borings of the ichnogenus Zapfella 
in the gastropod Galeodes (Volema) cornuta from the lower Miocene of Hungary. The 
photographs of Galeodes show grooves leading away from the narrow end of the aperture 
in several cases, much like Noll's (1875) drawing of Kochlorine hamata discussed above. 
Saint-Seine (1954) apparently considered these specimens specifically distinct from her 
Zapfella pattei, but in that genus. We could not examine that specimen because it was 
destroyed in World War II (F. F. Steininger, personal communication), but we were 
able to obtain the infested shell ofF. tarbelliana (IPUW-2522/84). Three of its burrows 
have a short, L. vza/r/jc-like trail with a few chevrons (growth lines) on the surface of 
a sunken roof (rostrum?) and apparently cement on the walls of the trench above the 
suspected rostrum. It seems that much of the rostrum and some of the cement had 
been eroded away. This is the best candidate for a fossil homologue of the L. viatrix 
rostrum system. Although more study is required, Zapfe's specimens most likely rep- 
resent primitive lithoglyptids, but from shallow rather than deep water. 

Other fossil analogues of the L. viatrix system, perhaps homologous with the 
Trypetesa system, are represented by Rogerella Saint-Seine {see especially Codez and 
Saint-Seine 1958) of the Mesozoic and Tertiary. Rogerella has one end of the burrow 
aperture wider than the other, and the narrow end produced to a greater or lesser extent 
into a "peduncular slit" lined on one or both sides with a "bourrelet" of calcareous 
lamellae, seldom well-preserved. Although originally limited to burrows in echinoid 
tests (Saint-Seine 1951, 1956), this genus was later broadened to include similar burrows 
in all sorts of substrates (Codez and Saint-Seine 1958), and now 4 species have been 
named {see also Schlaudt and Young 1960, Voigt 1967). 

In Rogerella lecointrei Saint-Seine, the bourrelets (one or a pair) are raised above 
the surface of the sea urchin test, and the calcareous lamellae are oblique, their medial 
edges pointing away from the main part of the aperture. The bourrelets are apparently 
continuous with a calcareous lining of the burrow, which becomes thinner and may 
disappear toward the burrow floor. If they were continuous across the peduncular slit, 



19 

which was never observed to be the case in these fossils, the bourrelets would resemble 
the chevron-incised trails of L. viatrix. If never closed over, then the bourrelets are 
like the calcareous rims in Trypetesa species. 

In Rogerella mathieui Saint-Seine the bourrelets are much more fragile and are 
very easily lost to erosion, due to the burrow widening suddenly below them. Its burrow 
is reported to be very deep beneath the entire opercular slit. The bourrelets are rarely 
preserved in the remaining 2 species, but Voigt (1967) notes that the narrow part of 
the aperture in R. caudata Voigt, which is often bent at a sharp angle to the rest of the 
aperture, is bounded on both sides by barnacle-secreted, calcareous deposits. Unlike 
R. lecointrei, these bourrelets are sunk into the surface of the host oyster, not raised 
above it. 

We propose that Rogerella bourrelets are of calcified cement laid down by the 
barnacle. The question remains as to whether the peduncular slit is natural or an artifact. 
A long burrow like that of L. viatrix would be similar to those of R. lecointrei if the 
former were moderately eroded to remove superficial cement and the rostrum itself 
removed by differential erosion, solution, or simple mechanical loss (the last being 
possible because the rostrum is separated from the cement by a chitinous cuticle). 
However, well-preserved specimens oi R. lecointrei exist that show no sign of substrate 
erosion (Saint-Seine 1951). Although the burrow shape is unknown in R. lecointrei, 
the very deep burrow of R. mathieui is quite unlike the long burrows of L. viatrix, 
which are not very deep, and become shallower away from the aperture. 

It may be more reasonable to assume that the burrows o^ Rogerella were produced 
by something akin to the Trypetesa species discussed above; the peduncular slit may 
be a real opening, not a product of surface erosion or rostrum loss. Saint-Seine's 
descriptive reconstruction of the Rogerella barnacle (Codez and Saint-Seine 1958) 
includes a "peduncle" attached at the end of the slit, supposedly the original larval 
attachment site. The slit had formed as the operculum moved away from the attachment 
site, and the lengthening peduncle was partly roofed over and protected by secreted 
bourrelets (calcareous cement). As in A. melampygos, the attachment site is fixed and 
no bodily translation occurred, just growth. The French authors cite Tomlinson's (1955) 
description of Trypetesa lateralis in support of this model, noting the homy attachment 
knob borne on a stalk (or "peduncle") longer than usual in the Acrothoracica. The 
undescribed species of Trypetesa from North Carolina, with its very large, distally 
anchored peduncular rudiment and cement secretions narrowing the open slit above 
it, is an almost exact analogue to Rogerella. A close phylogenetic relationship between 
the two genera cannot be discounted. 

Nomenclatural Significance of Fossil Acrothoracican Hard Parts 

As a matter of interest to paleontologists, fossil acrothoracican burrows are ich- 
nofossils (Hantzschel 1975), but the calcareous structures associated with them are 
sometimes body fossils. A rostrum (which may be present in Zapfe's 1936 specimens) 
is part of the barnacle's body, although structures composed entirely of mineralized 
cement (as we suspect for Rogerella's bourrelets) are not. The significance of this dis- 
tinction is that the International Code of Zoological Nomenclature, Third Edition (Art. 
23, g, iii) treats the names of ichnofossils differently from body fossils with regard to 
the Principle of Priority. It will be necessary in future paleontological studies of ac- 
rothoracicans to make explicit whether new taxa are ichnotaxa or not. 

Strategies of Motility 

Acrothoracicans have several different means of attaching themselves within their 
burrows, and most of them have a limited capacity for motility after settling. Motility 
is best defined functionally as displacement of the burrow aperture across its substrate; 
this may involve growth, bodily translation, or both. Various combinations of attach- 
ment mechanisms and growth patterns form coherent sequences of intermediate stages 
from the primitive condition exemplified by Weltneria hessleri and W. exargilla. 

There are three kinds of extra-mantle structures. A rostrum is a calcareous body 



20 



plate firmly attached to the mantle and invested in a chitinous cuticle. There is also 
mineralized cement, either anchoring the rostrum or the mantle in place, and/or serving 
a protective function. Most non-rostrate acrothoracicans attach themselves to the bur- 
row wall by a secreted, non-calcareous cement disc that incorporates successively larger 
parts of the exuvia at each molt (known exception: Lithoglyptes indicus with a calcareous 
cement disc). Mineralized and organic cement may be produced by different parts of 
the mantle in the same species, but often only one or the other is present. 

Our conception of the sequential alterations from a primitive, immotile acro- 
thoracican with a vertical rostrum held in place by mineralized cement (e.g., Weltneria 
exargilla), presently confirmed only in bathyal and abyssal forms, is shown in Figure 
8. One strategy is to retain the rostrum and mineralized cement, but to add a horizontal 
component to rostral growth. This keeps the mantle protected by a hard cover as the 
aperture moves small distances (e.g., Weltneria griggi). The selective advantages of 
motility, allowing resituation of the mantle opening if the original settling site proved 
unfavorable, led to a rotation of the mantle so it could remain attached to the under 
side of a horizontal rostral burrow roof Lithoglyptes tectoscrobis retains a narrow 
connection to the older end of the burrow (its mantle tube). Lithoglyptes viatrix has 
lost even this connection, making it the first and only truly motile acrothoracican known. 

Another highly successful strategy in shallow seas was to lose the rostrum. Lith- 
oglyptes indicus, with its attachment disc of calcareous cement, may illustrate an early 
stage in this process. In all other cases known, the calcareous component of the cement 
stopped being incorporated, at least in the cement disc. However, mineralized cement 
is still produced near the operculum in some forms where it has been convergently 
adopted as a roofing material for a shifting aperture [Australophialus melampygos, 
Trypetesa (point already made for T. lampas by Kamens 1981), and Rogerella]. All 
such species rely on mantle growth to force the aperture along. In some cases {A. 
melampygos, T. lampas) the distal end of the mantle is broadly stuck to the burrow 
wall so the animals cannot move. Their capacity to reposition themselves is more 
limited than the undescribed Trypetesa species and R. lecointrei, whose burrow aper- 
tures are as adjustable as those of L. viatrix. The Carolinian Trypetesa is barely attached 
to the distal end of the burrow, but part of the mantle remains at the initial site of 
attachment. The peduncular rudiment is free to grow and elongate as the body and the 
opercular part of the mantle move farther from their initial position. 

The last stage in this sequence is the loss of calcareous structures altogether (e.g., 
A. utinomii, L. spinatus). Possibly most extant acrothoracicans fall into this category. 
However, aside from the presence of chitin (exuvia), the composition of few cement 
discs is known, and we suspect a facultative ability to produce a short, mineralized 
cement roof may not be uncommon, given the obvious advantages of post-settlement 
reorientation. 

Paleobiology 

There are three important considerations that emerge from the foregoing: 1) Ac- 
rothoracicans first appeared in the Paleozoic and apparently occupied a greater variety 
of skeletal substrates in the Mesozoic than they do today [brachiopods, belemnites, 
and echinoids as well as corals, bryozoans, and gastropod and bivalve mollusks, for 
example (Tomlinson 1969)]. At least part of this additional diversity was due to species 
with hard parts {Rogerella in echinoid tests); 2) acrothoracicans with obvious calcareous 
hard parts were apparently more abundant in shallow water in the Mesozoic and 
Tertiary than they are today; and 3) extant shallow- water acrothoracicans with calcareous 
hard parts tend to occupy relictual regions such as New Zealand {Australophialus), or 
biogeographical transition zones {Trypetesa; Newman 1979), while those with the most 
primitive or plesiomorphic calcareous hard parts are found in the deep sea ( Weltneria 
species and Lithoglyptes species). All this suggests that hard parts have not been evo- 
lutionarily favored except in certain refugial habitats. Whether this has to do with small 
size as a refuge from predation in most extant acrothoracicans (those with calcareous 



21 



parts tending to be relatively large), or to more subtle metabolic or energy budget- 
related causes, is unclear. 

It was noted above that the calcareous hard parts of Lithoglyptes viatrix from the 
Pacific were very similar to those of a Lower Miocene form from Hungary, described 
and figured by Zapfe (1936). This is not surprising because, as Fleming (1979) has 
pointed out, much of the Tertiary marine fauna of the Indo-Pacific, replacing that which 
became extinct in the Cretaceous, is Tethyan and holds its closest known affinities with 
the Tertiary marine fauna of Europe. 

Conclusions 

We have distinguished several different kinds of acrothoracican burrows and cal- 
careous structures associated with them, and discussed the implications for the behavior 
and morphology of the housed barnacles. These findings apply equally well to extant 
and fossil burrows, for we have discovered living analogies among several unusual 
kinds of fossil acrothoracican burrows. Neontologists should now be able to correctly 
interpret acrothoracican extra-mantle structures, and paleontologists can use such struc- 
tures to better reconstruct the morphology, life style, and ecological pressures on the 
barnacles that once inhabited the burrows they may find. 

Acknowledgments 

We thank Dr. R. W. Grigg (Hawaii Institute of Marine Biology) and Dr. S. D. 
Cairns (USNM) for loaning us host corals; Drs. W. Klepal and F. F. Steininger (Uni- 
versity of Vienna) for arranging a loan of Zapfe's bored fossil snail; Dr. J. Tomlinson 
(San Francisco State University) for letting us examine the undescribed Trypetesa 
species and its burrow, and to prepare and publish the figure of their relationships; Dr. 
B. A. Foster (Auckland University) for sending specimens of Australophialus melam- 
pygos in Perna shells; Dr. V. A. Zullo (University of North Carolina at Wilmington) 
for loaning us a copy of Kamens' thesis; and N. Freres for preparing some of the 
illustrations. Comments on the manuscript by H. R. Spivey, J. T. Tomlinson, and two 
anonymous reviewers were greatly appreciated. One of us (MJG) was aided by an NSF 
Graduate Fellowship and by two travel grants to Hawaii from Scripps Institution of 
Oceanography. This work was partly supported by NSF Grant DEB 78-15052. 



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^^A^"^ 



^^^rS^Y 



TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 



Volume 21 Number 2 pp. 23-55 29 October 1985 



The Sangamon interglacial vertebrate fauna from 
Rancho la Brisca, Sonora, Mexico 

Thomas R. Van Devender 

Arizona- Sonora Desert Museum. Route 9, Box 900, Tucson, AZ 85743 USA 

Amadeo M. Rea 

San Diego Natural History Museum, P.O. Box 1390. San Diego. CA 92112 USA 

Michael L. Smith 

Museum of Zoology, University of Michigan, Ann Arbor, MI 48109 USA 

Abstract. Bones of 5 1 species of vertebrates including fish, amphibians, reptiles, birds, and mam- 
mals were recovered from a sedimentary deposit at Rancho la Brisca in north-central Sonora, Mexico. 
The fauna was preserved in a marshy cienega habitat with 49.0% of the species and 87.2% of the 
identified bones representing aquatic and semiaquatic animals. The most common animals in the fauna 
are Kinosternon sonoriense (Sonoran Mud Turtle) and Rana ''pipiens'' -complex (Leopard Frog). 

The presence of Bison species (Bison) in association with Mammuthus species (Mammoth), Equus 
cf. tau (Pygmy Onager), and Camelops species (Camel) places the fauna in the Rancholabrean Land 
Mammal Age. Bufo cf kelloggi (Little Mexican Toad), B. mazatlanensis (Sinaloa Toad), Leptodactylus 
melanonotus (Sabinal Frog), Pternohyla fodiens (Burrowing Treefrog), and Masticophis cf mentovarius 
(Tropical Whipsnake) are subtropical thomscrub or Sonoran Desert animals that presently occur to the 
south and/or west of la Brisca. Bufo alvarius (Colorado River Toad), cf Callisaurus draconoides (Zebra- 
tailed Lizard), and Sceloporus cf clarkii (Clark's Spiny Lizard) are other Sonoran Desert animals that 
suggest a paleoclimate with warm winters and a well-developed summer monsoon. The best modem 
analog for the paleocommunity would be about 240 km SSE on the Rio Yaqui. The subtropical elements 
in the la Brisca fauna make it unlikely that the fauna was deposited during a glacial period, considering 
that the Late Wisconsin paleoclimatic reconstructions for Arizona based on plant remains in packrat 
middens suggest glacial climates with mild, wet winters and cool, dry summers. The fauna represents 
an interglacial environment subsequent to the appearance of Bison about 150 000 years ago in the 
Sangamon Interglacial and with a climate similar to that of the Late Holocene of the last 4000 years. 

The distributions of fish and mud turtles suggest past stream connections between the Gila River 
drainage in southeastern Arizona and the rivers in Sonora. In contrast, Pseudemys scripta (Yaqui Slider) 
apparently never entered Arizona, although it reaches north-central Sonora today. 

Resumen. Un deposito aluvial en Rancho la Brisca, Sonora, ha producido fosiles de 5 1 vertebrados. 
Se incluyen peces, amfibios, reptiles, mamiferos, y aves. El 49% de la especies y el 87.2% de los huesos 
identificados pertenecen a animales acuaticos o semiacuaticos, confirmando la surgerencia que el ya- 
cimiento representa una cienega. Los huesos mas corrientes pertenecen a Kinosternon sonoriense (Tor- 
tuga de Barro Sonorense) y Rana ''pipiens" -complex (Rana Pardal). La fauna se refiere a la edad de 
mamiferoterrestre de Rancholabrea implicado por las presencia de Bison species (Bisonte) con Mam- 
muthus species (Mamut), Equus cf tau (Caballo), y Camelops species (Camello). 

Bufo cf. kelloggi (Sapito Mexicano), B. mazatlanensis (Sapo Sinaloense), Leptodactylus mela- 
nonotus (Rana Sabinal), Pternohyla fodiens (Rana Arborea Minera), y Masticophis cf mentovarius 
(Elicante) se ubican hoy al sudeste de la Brisca en el Desierto Sonorense o en al bosque espinoso. Se 
incluyen tambien otros animales del Desierto Sonorense como Bufo alvarius (Sapo del Rio Colorado), 
cf Callisaurus draconoides (Lagartija con Cola de Cebra), y Sceloporus cf clarkii (Lagartija Espinosa 
de Clark). Estos animales indican un clima en cual las temperaturas del inviemo son moderadas y 
occurren fuertes lluvias estivales. 

Clima semejante al que se sugiere en encuentra 240 km SSE cerca el Rio Yaqui. El yacimiento 
probablemente no se formo en periodo glacial ya que se encuentran varies elementos subtropicales. 
Reconstrucciones del clima de Arizona durante el periodo Wisconsin insinuan el mayor porcentaje de 



24 



la precipitacion anual en el inviemo, temperaturas moderadas en el inviemo, y veranos secos pero 
atemperados. La fauna en vez se refiere a un interglacial despues de 150 000 anos en el Sangamon 
Interglacial y con clima semejante al Holoceno Ultimo hace 4000 anos a hoy. Las distribuciones de 
los paces y tortugas de barro sugieren conexiones historicas entre los desagues de Arizona y Sonora. 
Sin embargo, Pseudemys scripta (Resbalador Yaqui) no aparece en Arizona aunque hoy se encuentra 
en la parte norte-central de Sonora. 

Introduction 

In 1975, a vertebrate fossil locality near Rancho la Brisca was discovered during 
a survey of the archaeological and paleontological resources of the Rio San Miguel 
drainage in Sonora, Mexico, by the Centro Regional del Noroeste of the Instituto 
Nacional de Antropologia e Historia in Hermosillo. We report specimens collected 
from 1975-1982 (Table 1). In June 1978, 29 burlap bags of sediment were washed 
through fine mesh (ca. 2 mm) screens to recover bones of small vertebrates. Most of 
the fossils have been deposited into the vertebrate paleontological collections in the 
Instituto de Geologia in Mexico City (IGCU 2546-260 1). Individual specimen numbers 
were not provided and have not been included in the text for specimens deposited in 
this collection. Duplicate specimens and casts are in the University of Arizona Lab- 
oratory of Paleontology (UALP) collections. The site is UALP locality #7627; all 
specimen numbers in the text are UALP catalog numbers. The amphibian, reptile, and 
small mammal material was identified using Van Devender's osteological collection 
(TRV). Terminology for most of the anuran post-cranial elements follows that of Gaup 
(1896). Bird remains were identified using Rea's osteological collection (AMR). Fish 
remains were compared to skeletons at the University of Michigan Museum of Zoology 
(UMMZ). Extinct mammals and birds were identified by comparison with fossils in 
the UALP and the Los Angeles County Museum (LACM) collections. The present 
distributions of amphibians and reptiles in Sonora were determined from specimens 
in the herpetological collection in the Department of Ecology and Evolutionary Biology, 
University of Arizona (UAZ). Extinct animals in the systematics section are marked 
by daggers (f). 

Environmental Setting and Geology 

The fossil locality is in north-central Sonora near Rancho la Brisca on the Rio 
Santo Domingo, an upper tributary of the Rio San Miguel (Fig. 1). Rancho Agua Fria 
and the old mission site of Saracachi are 5 km S where there is a large cienega (marshy 
area) in the stream valley (Fig. 2). The site is 33 km NE of Cucurpe, 180 km NNE of 
Hermosillo, and 90 km S of the United States border. 

The vegetation at the site is a desert-grassland at about 1000 m elevation that is 
between the Arizona Upland subdivision of the Sonoran Desert (Shreve 1964) and 
Mexican oak woodlands (Fig. 3). Important perennials on the slopes near the site include 
Prosopis velutina (Velvet Mesquite), Juniperus erythrocarpa (Redberry Juniper), Mi- 
mosa biuncifera (Wait-a-minute Bush), and M. dysocarpa (Gatuno). Quercus emoryi 
(Emory Oak or Bellota), Celtis reticulata (Netleaf Hackberry), and Juglans major (Ar- 
izona Walnut) are on areas with deeper soil below. Salix nigra (Goodding Willow), 
Fraxinus pennsylvanica (Velvet Ash), Populus fremontii (Fremont Cottonwood), and, 
locally, P. monticola (Sonoran Cottonwood), occur along the Rio Santo Domingo. The 
canyon flora includes Ficus petiolaris (Fig) at its northern limit and occasional Acer 
grandidentatum (Big Tooth Maple) at its southern limit. The stream is perennial and 
harbors such species as Gila purpurea (Yaqui Chub), Rana ''pipiens" -complex (Leopard 
Frog), Kinosternon sonoriense (Sonoran Mud Turtle), and Thamnophis cyrtopsis (Black- 
necked Garter Snake). A disjunct, southern population of Sciurus arizonensis (Arizona 
Gray Squirrel) lives in the riparian trees. The area is used mostly for grazing with some 
local agriculture and gold mining. 

Climatic records for Saracachi at 930 m elevation are available in Hastings and 
Humphrey (1969). The mean annual temperature is 16.5°C; the coldest and hottest 
months are January (8.3°C) and July (25.3°C), respectively. The mean annual precip- 



25 




Figure 1 . Map of Sonora and adjacent Arizona. Stippled area is Sinaloan thomscrub vegetation after Brown 
and Lowe (1977). Boundary of Sonoran Desert after Shreve (1964). 



itation is 466.8 mm, with 64% falling from June through August. These records are 
based on only a few years of data (1942-1946), but are similar to longer records for 
Cucurpe and Arizpe. 

Between Rancho Agua Fria and Rancho la Brisca, the stream has incised into a 
narrow canyon in the coarse, well-indurated stream gravels. Near la Brisca, the canyon 



26 




Figure 2. Saracachi Cienega in April 1977. Rana '^ pipiens" -comx)\&\ (Leopard Frog) and Kinosternon 
sonoriense (Sonoran Mud Turtle) are common. Pseudemys scripta (Yaqui Slider) was observed in the open 
water in middle of photo. The trees on edge of water are Salix nigra (Goodding Willow), Celtis reticulata 
(Netleaf Hackberry), and Prosopis velutina (Velvet Mesquite). The columnar cactus on hill in background is 
Carnegiea gigantea (Saguaro). 




;:3 



Figure 3. General view of the Rancho la Brisca vertebrate fossil locality in April 1976. Deposits are on 
the hillside in the center of photo obscured by trees. Most of the trees are Prospis velutina (Velvet Mesquite), 
with a few Quercus emoryi (Bellota). 



27 




Figure 4. Unit 2 of the Rancho la Bnsca venebraie fossil locality. Fossil bone was weathering out of the 
fine-grained sediments in lower center of photo. Screen wash samples came from this area as well. 



widens where the fossils were found, about 1 5 m above the canyon floor in a small 
unit of remnant sediments deposited on the gravels (Fig. 4). There are three well-defined 
sedimentary units in the stratigraphic section: (1) a lower buff mudstone with a little 
gravel, about 3 m thick; (2) a middle buff mudstone with less gravel, about 2 m thick; 
and (3) an upper reddish gravel, about 2 m thick. Bone was found in the lower two 
units in fine clays with sparse gravel up to about 10 mm in size. The bone is well- 
mineralized and mostly dark brown or black. Fragile specimens (e.g., frog ilia and snake 
vertebrae) show no signs of transport damage, suggesting in situ deposition. Samples 
from the two mudstones, extracted for pollen using both acid and heavy liquid extraction 
techniques, were sterile (R. S. Thompson and V. Markgraf, personal communication). 
Two deposits with similar lithologies and perched positions on the rim of the valley 
were seen within 5 km of the la Brisca site (R. S. White, personal communication). 

Annotated Account of Fossil Taxa 

Class Osteichthyes— Bony Fishes 

Order Cypriniformes— Minnows and Minnowlike Fishes 

Family Catastomidae— Suckers 

Catostomus wigginsi Herre and Brock— Opata Sucker 

Material. —MdiXxWa, dentary, metapterygoid and ceratohyal. 

Comments.— Tht fossils are from suckers of 80-115 mm standard length (SL). 
Comparative material of C wigginsi (UMMZ 202388-S) is from the Rio Santo Do- 
mingo at Rancho la Brisca. 



28 

Castostomus wigginsi is distinguished from the other five described species of 
Mexican Catostomus on characters of the dentary. The gnathic ramus of the dentary 
is more attenuate in C wigginsi than in C. clarki (Desert Sucker) and bears a narrower 
groove for the labial cartilage. The gnathic sensory canal pore is not united with the 
crest for Meckel's cartilage to form a single complex structure as it is in C. bernardini 
(Yaqui Sucker) and C. conchas (Rio Conchos Sucker), and the sensory pore is nearer 
the symphysis than is the crest for Meckel's cartilage. The coronoid process of the 
dentary is not deflected laterally as in C. plebeius (Rio Grande Sucker); the posterior 
surface of the gnathic ramus is flat, not concave; the anterior end of the groove for the 
labial cartilage is visible in mesial view. Catostomus wigginsi is distinguished from C. 
insignis (Sonoran Sucker) by the highly elevated coronoid process in the former. 

The dorsal keel of the maxilla of C. wigginsi is distinct from that of Catostomus 
plebeius in that it is flexed anteroventrally. In C. wigginsi the ceratohyal is long and 
slender, much less robust than in C. plebeius, C. bernardini, or C. insignis, and is 
without ventral ornamentation as in C. insignis. The la Brisca fossils agree with C. 
wigginsi in the above characters. 

This is the only fossil record for C wigginsi and the genus Catostomus reported 
from Mexico. Catostomus wigginsi is endemic to the Rio Sonora and its tributary, the 
Rio San Miguel, although there is a single record for the Rio Moctezuma, tributary to 
the Rio Yaqui (UMMZ 161467; Hendrickson et al. 1980). Catostomus bernardini has 
been collected once in the Rio Sonora system (UMMZ 161453); it is otherwise known 
from Pacific slope drainages from the Rio Yaqui to the Rio Sinaloa. Since C. wigginsi 
has not been collected subsequently from the Rio Yaqui drainage, nor C. bernardini 
from the Rio Sonora, we regard these records as erroneous. 

The Opata Sucker is a small species of Catostomus; breeding individuals are less 
than 1 10 mm SL at Rancho la Brisca today. It is typically associated with moderate 
to swift currents and sand or gravel substrate in rivers or small streams with pools or 
other cover. 



Family Cyprinidae— Minnows 
Agosia chrysogaster Girard— Longfin Dace 

Material. —Right pharyngeal arch lacking posterior limb and fourth tooth. 

Comments. —The fossil resembles recent material of Agosia chrysogaster from the 
Rio San Miguel drainage (UMMZ 202389-S). The pharyngeal arch is attenuate and its 
anterior limb is shorter than its dentigerous portion. The teeth bear weak hooks and 
are moderately compressed, but are not as compressed or crowded as in species of 
Pimephales and Campostoma; they are more closely spaced than in Notropis ornatus 
(Ornate Shiner) or N.formosus (Beautiful Shiner). The fossil differs slightly from recent 
material of A. chrysogaster in having smaller terminal hooks on the teeth. 

Agosia occurs naturally in the Gila and Bill Williams drainages of southwestern 
United States (Minckley 1973) and in the Magdalena, Sonora, Yaqui, and Sinaloa river 
systems of Mexico. These are all considered to be A. chrysogaster, although the Mexican 
populations may be a distinct species (Miller 1958). A. chrysogaster is abundant in 
most Sonoran Desert streams below 1 500 m (Minckley 1973, Hendrickson et al. 1980); 
it has not been reported previously as a fossil. 



Genus and species indeterminate 

Material. —A fragmentary left opercle. 

Comments. —This bone can be assigned to the Cyprinidae based on the shape of 
the dilator process; the articulating cotyla and most of the body of the bone are missing. 
The specimen is too large to be Agosia, Campostoma, Notropis formosus, N. ornatus, 
or Pimephales. It agrees in size with Gila, but diagnostic features are lacking. 



29 

Cyprinidontiformes— Pupfish and Killifish 

Family Poeciliidae — Topminnows 

Poeciliopsis accident alis Baird and Girard — Gila Topminnow 

or 
P. monacha-occidentalis —All-female Topminnow 

Material. —Two left opercles. 

Comments. —The dilator process of the opercle is rounded and does not extend 
beyond the dorsal margin of the opercle. The articulating cotyla is oblong dorsoventrally 
and matches modem material in shape and arrangement of its supporting struts. Poe- 
ciliopsis occidentalis and P. monacha-occidentalis are distinguishable on dental char- 
acters which, unfortunately, are not evident on the fossil material. 

The natural range of the Gila Topminnow includes the Gila River of Arizona and 
New Mexico and the Pacific coastal drainages of Sonora south to the Rio Mayo. In the 
Mexican part of its range, it is host to the all-female hybridogenetic form, P. monacha- 
occidentalis. Both forms occur at Rancho la Brisca today, although P. monacha-occi- 
dentalis was rare (2.2%) in our field collection which constitutes one of the northernmost 
records of the all-female form {see Moore et al. 1970). Poeciliopsis occidentalis was 
widespread and abundant in two surveys of Sonoran fishes (Branson et al. 1960, Hen- 
drickson et al. 1 980). It is associated with moderate current below riffles or along stream 
margins and characteristically occurs over sandy substrates (Minckley 1973). We col- 
lected it in the Saracachi Cienega (Fig. 2). 

This is the only fossil poeciliid reported from Mexico. Alvarez and Aguilar (1957) 
described a fossil poeciliid, Poeciliopsis maldonadoi, from deposits of unknown age 
(possibly Recent) in El Salvador. Some of that material later proved to be of the genus 
Poecilia, and P. maldonadoi may prove to be a synonym of the living species P. 
turrubarensis (Rosen and Bailey 1963). 



Class Amphibia— Amphibians 

Order Anura— Toads and Frogs 

Family Bufonidae— Toads 

Bufo alvarius Girard— Colorado River Toad 

Material. —Frontoparietals (Fig. 5 A), scapula (1 1599), ilia (3; 1 1600; Fig. 5B). 

Bufo cf. alvarius 

Material. -Dentaries (2; 11601), exoccipital, nasal, vertebrae (5; 11603-11604), 
humeri (2; 1 1602), radioulna. 

Comments. —The fossils are from toads of 1 10-160 mm snout-vent length (SVL). 
Today only B. alvarius and B. marinus (Marine Toad) reach this and larger sizes. Bufo 
woodhousei bexarensis (Friesenhahn Cave Toad), an extinct late Pleistocene form in 
Texas, reached body lengths of 160 mm, but had a narrow frontoparietal with tubular 
dorsal ornamentation (Mecham 1959, Tihen 1962a) quite different than the la Brisca 
fossil. Bufo alvarius and B. marinus are in the B. valliceps (Gulf Coast Toad) species 
group of Tihen (1962/?). Both species have wide frontoparietals shaped similar to those 
of the fossil, but B. marinus has heavier, more rugose dorsal ornamentation with 
prominent ridges oriented obliquely to the anterior-posterior axis of the bone (Fig. 5 A). 
The anterior edge of the frontoparietal in our reference specimens is more squared-off' 
than in the fossil. The ilia referred to B. alvarius have a broader dorsal prominence 
without the pronounced knob of B. marinus (Fig. 5B). The scapula of B. alvarius differs 
from that of B. marinus in that the articular surface is slightly smaller, and in that the 
acromial portion is relatively narrow. The larger la Brisca toad fossils could all be from 
B. alvarius, but B. marinus cannot be eliminated from consideration on the bones 
listed as B. cf. alvarius. 



30 



Fig. A 



rO 



mm 



•■5 







Fig. B 



i:s?i^^22ft^ 




Figure 5. Bufo alvarius (Colorado River Toad). A. Right frontoparietal, B. Right ilium (UALP 10151). 

This is the only Rancholabrean fossil record for B. alvarius. Lindsay (1 984) reported 
B. alvarius from Irvingtonian deposits from the mouth of the Colorado River in the 
Gulf of California at El Golfo, Sonora (C. A. Shaw, personal communication 1985). 
Tihen {\962a) identified Bufo cf alvarius from the Blancan Benson (=Post Ranch) 
Fauna in Cochise County, Arizona. Johnson et al. (1975) dated this fauna at 3. 1 million 
years ago using the paleomagnetic stratigraphy in the San Pedro River Valley. Bufo 
alvarius is a large toad restricted to desertscrub and thomscrub plant communities in 
the Sonoran Desert from southern Arizona to northern Sinaloa (Fouquette 1970). It 
presently occurs near the la Brisca fossil site. Bufo marinus is a toad of more tropical 
environments that reaches its northern limit in southernmost Sonora. 



Bufo cf cognatus Say— Great Plains Toad 

Material— 'L. humerus. 

Comments.— ThQ humerus lacking the medial crest was from a female toad of 
about 60 mm SVL. The bone was relatively poorly ossified, and the radial condyle was 
unfused. The fossil is similar to the humeri of reference B. cognatus of the same size, 
although it is slightly more robust. Bufo cognatus was reported as a Late Wisconsin 
fossil from Friesenhahn Cave and the Groesbeck Local Fauna in Texas (Holman 1 969a). 



31 

Bufo cognatus occurs from the Great Plains south into south-central Mexico and west 
to southeastern California, Baja California, and most of Sonora. 

Bufo cf. kelloggi Taylor— Little Mexican Toad 

Material. —Humeri (6L, 3R; 1 1605), sacral vertebra. 

Comments. —The fossils are from individuals of 30-35 mm SVL. All appear to 
be males, although the medial crest is only weakly developed in B. kelloggi. The humeri 
of B. retifonnis and B. punctatus are not as well ossified at this size. Bufo debilis is 
closer in size to B. kelloggi, but most mature at 40-45 mm SVL. Male Leptodactylus 
melanonotus are of similar size, but have better developed medial crests, more flattened 
shafts between the middle and the radial condyle (eminentia capitalis of Gaup 1896), 
and the lateral crest and epicondyle are equally well-developed. 

Bufo kelloggi has not been reported previously in the fossil record. Bufo kelloggi 
is the smallest toad in the Bufo punctatus group of Ferguson and Lowe (1969) which 
also includes B. punctatus, B. retiformis, and B. debilis. It is found in coastal subtropical 
lowlands from Nayarit to as far north as central Sonora in the vicinity of Hermosillo, 
with an outlying population near Santa Ana (Hulse 1977). The la Brisca site is northeast 
of its present range. 

Bufo mazatlanensis Taylor— Sinaloa Toad 

Material.— K. basioccipital/frontoparietal, humeri (2L; 1 1607), ilia (2L, 2R; 1 1606; 
Fig. 6). 

Bufo species— Toad 

Material— Eihmoids (2), basioccipital, atlas, sacral vertebra, urostyle, humerus, 
radioulnae (3; 11610), tibiofibulae (5; 1 1609). 

Comments. —The fused basioccipital and frontoparietal are from a toad of about 
90 mm SVL. The frontoparietal is broad and moderately rugose without a well-de- 
veloped ridge for cranial crests. Bufo alvarius also has a broad frontoparietal without 
a crest, but has a strongly papillose or echinate dorsal surface. The frontoparietal of B. 
cognatus is narrow with a well-developed cranial crest. The condyloid fossa lateral to 
the occipital condyle is relatively larger in B. alvarius than in B. mazatlanensis and B. 
cognatus. The fossil resembles reference B. mazatlanensis. 

The humeri referred to Bufo mazatlanensis are from a female of about 65 mm 
SVL, and a male of about 82 mm SVL. The radial condyle is well-rounded; the ulnar 
or medial epicondyle is well-developed; the lateral crest and lateral epicondyle are 
present, but not protruding. 

The ilia referred to Bufo mazatlanensis are all from toads of 75-80 mm SVL and 
have low, broad dorsal prominences that are fairly flat on top, rugose or not, and with 
a broad, deep ventral acetabular expansion (Fig. 6). The dorsal prominences of B. 
alvarius, B. cognatus, B. woodhousei, and B. microscaphus are higher. The ventral 
acetabular expansion of 5. alvarius is deep, but not broad. The bones identified as Bufo 
species could all be from B. mazatlanensis. 

Bufo mazatlanensis does not have a previous fossil record. It is a member of the 
B. valliceps group found in the tropical lowlands of northwestern Mexico from southern 
Sinaloa northward to central Sonora. The northernmost collections are from the narrows 
of the Rio Sonora near Ures 140 km S of la Brisca. 

Bufo punctatus Baird and Girard — Red-spotted Toad 

or 
Bufo retiformis Sanders and Smith— Sonoran Green Toad 

Material. -WwrnQvi (3R, 4L; 10150, 11608). 

Comments.— ThQSQ humeri are from mature male toads 45-55 mm SVL. The 
radial condyles are well-ossified. The male medial crests may be well-developed. Male 



32 




Figure 6. Left ilium (UALP 1 1606) of Bufo mazatlanensis (Sinaloa Toad). 



Hylactophryne augusti are similar in size to the fossils, but the distal end of the humerus 
is relatively wider in this species, and the ulnar and epicondyles are well-developed. 
The humeri of most other Bufo and Rana are larger. The humeri of B. punctatus and 
B. retiformis are very similar to each other. 

Bufo punctatus has been recorded from the Late Pleistocene and Holocene sedi- 
ments of Dry Cave, Guadalupe Mountains, southeastern New Mexico (Holman 1970), 
and Howell's Ridge Cave, Little Hatchet Mountains, southwestern New Mexico (Van 
Devender and Worthington 1977). Bufo punctatus was reported from Late Wisconsin/ 
Early Holocene deposits in Deadman Cave, Santa Catalina Mountains, Pima County, 
Arizona (Mead et al. 1984). Its bones were also found in packrat middens from the 
Sonoran Desert (Van Devender and Mead 1978). Two Late Wisconsin midden spec- 
imens from near Tucson, Arizona, were associated with a radiocarbon date of 12 1 30 ± 
500 B.P. (radiocarbon years before present). Three Early Holocene midden specimens 
from the Whipple Mountains, California, were associated with dates of 10 930 ± 170 
B.P. and 10 330 ± 300 B.P. Bufo retiformis does not have a previous fossil record. 

Bufo punctatus is widespread in many habitats in the southwestern United States 
and Mexico. Bufo retiformis is a Sonoran Desert animal found from central Sonora 
north of Guaymas into south-central Arizona in Organ Pipe Cactus National Monument 
and on the Papago Indian Reservation (Hulse 1978). 



Family Hylidae— Treefrogs 
Hyla arenicolor Cope— Canyon Treefrog 



Material. -\\\2i{^U 8R; 11636). 



Hyla species— Treefrog 

Material. —Vertebrae (2; 11611), sacral vertebrae (3; 11612), urostyles (2; 11613), 
radioulna, tibiofibula. 

Comments. —The ilia are referred to H. arenicolor because: (1) the dorsal and 
ventral acetabular expansions (posterior and anterior pelvic spines of Gaup 1896) are 
subequal (the dorsal acetabular expansion is relatively smaller in H. regilla); (2) larger 



33 

size for maturity of the bone than in H. eximia; (3) relatively larger acetabulum for 
size of ilial head than in H. cadaverina; (4) a relatively low, broad dorsal prominence 
without a well-developed "knob" compared to H. regilla and H. eximia. Pternohyla 
fodiens is a larger treefrog which has the dorsal prominence oriented more dorsally 
than in Hyla. The fossils appear to have ossified at a relatively smaller body size (by 
40 mm SVL) than does H. arenicolor today, and the "knob" on the ilial prominence 
is somewhat better developed. The la Brisca bones identified only as Hyla species could 
be from H. arenicolor as well. The sacral and trunk vertebrae resemble Hyla. but 
apparently are from mature individuals with body sizes of 35-40 mm SVL rather than 
today's 40-45 mm SVL. The urostyles, radioulna and tibiofibula are not sufficiently 
distinct to refer them to species. 

The only previous Late Pleistocene and Holocene records for Hyla arenicolor are 
from Howell's Ridge Cave, New Mexico (Van Devender and Worthington 1 977). Today 
it is widespread in canyon habitats in the mountains of the southwestern United Stales 
and Mexico and lives at the fossil locality today. 

Pternohyla fodiens Boulenger— Burrowing Treefrog 

Ma?ma/. — Basioccipital, dentary, humerus. 

Comments. —The basioccipital is referred to P. fodiens because: (1) the occipital 
condyle is a rounded knob rather than a flattened, elongate surface; (2) the epiotic 
eminence (terms follow Sanders 1953) is a prominent knob; (3) the prootic-transverse 
process is expanded; (4) the basioccipital is not fused to the frontoparietal as it is in 
adult Hylactophryne augusti and Bufo mazatlanensis. 

The fossil dentary is referred to P. fodiens because: (1) it is larger than in Lepto- 
dactylus melanonotus and Bufo kelloggi, but smaller than in female Hylactophryne 
augusti, Bufo alvarius, B. cognatus, and B. mazatlanensis; (2) the medial flange is well- 
developed on the ventral border of Meckel's canal just anterior to the articular surface 
as in Hyla, but not Bufo punctatus and B. retiformis; (3) the dentary is thicker and 
curves more laterally and ventrally than Hyla arenicolor. 

The fossil humerus has the broad distal end with the narrow shaft of the hylids, 
but it is larger (ca. 60 mm SVL) and stouter than adult Hyla arenicolor (45 mm SVL). 
The humerus of Smilisca baudini, a large subtropical treefrog, is not well-ossified at 
65 mm SVL and has a broader distal end. Both the lateral or ulnar epicondyle project 
distally, while the radial condyle projects beyond both. 

Pternohyla fodiens does not have a previous fossil record. It lives in dry subtropical 
habitats from Jalisco and Michoacan northward along the west coast of Mexico through 
Sinaloa and Sonora and into Arizona on the Papago Indian Reservation (Trueb 1969). 
The la Brisca site is probably just to the northeast of the nearest Sonoran populations. 

Family Leptodactylidae— Tropical Frogs 
Hylactophryne augusti (Duges)— Barking Frog 

Ma/ma/.— Scapula, tibiofibulae (3; 11640; Fig. 7). 

Comments.— ThQ fossils are from frogs of about 45-55 mm SVL. Hylactophryne 
augusti is sexually dimorphic with females reaching 90 mm SVL and males about 55 
mm SVL. Reference skeletons of female H. augusti of 63 mm, 67 mm, and 89 mm 
SVL, as well as of many species of Eleutherodactylus and Leptodactylus, were available 
for comparison. 

The scapula was referred to H. augusti because: (1) the acromion and glenoid 
portions of the scapula are not parallel as in Rana; (2) the anterior margin in the "waist" 
is less curved than in Bufo and Scaphiopus; (3) the notch between the acromial and 
glenoid portions of the scapula is relatively broad and angled; (4) the articular surface 
is relatively large. 

Bufo and Scaphiopus (Pelobatidae) have relatively short tibiofibulae with the ends 
much wider than the middle. Rana (Ranidae) and Hyla (Hylidae) have longer, slender 
tibiofibulae that are flexed in the middle. The fossils and the leptodactylid reference 



34 



rO 

mm 
1-5 



Figure 7. Tibiofibula of Hylactophryne augusti (Barking Frog). 



specimens are moderately long and have straighter shafts with the ends and middle 
less disparate in size than in Bufo and Scaphiopus (Fig. 7). The distal end of the la 
Brisca fossil is missing, but the proximal end has well-ossified epiphyses with prominent 
lateral ridges similar to those on our reference leptodactylids. This articular surface in 
bufonids, pelobatids, ranids, and hylids is less ossified and usually separates from the 
shaft in maceration. The fossils are somewhat more robust than the reference specimens. 
Hylactophryne (as Eleutherodactylus) augusti was reported from Late Wisconsin 
deposits in Frieshenhahn Cave, Bexar County (Mecham 1959) and Schulze Cave, 
Edwards County (Holman \969b), Texas. Hylactophryne augusti is a secretive, rock- 
dwelling frog that is found in many habitats from southeastern Arizona (Bezy et al. 
1966), southeastern New Mexico, and central Texas south through Mexico to the 
Isthmus of Tehuantepec (Zweifel 1967). In Arizona, it is rare in habitats similar to the 
la Brisca fossil site. 

Leptodactylus melanonotus (Hallowell)— Sabinal Frog 

Material— YtrXobrsiQ (2; 11617), ilia (3R, L; 11616), scapula, humerus (R, L; 
11614), radioulna (11615), tibiofibulae (5). 

Comments.— Tht vertebrae were referred to L. melanonotus because: (1) of the 
small size (ca. 40 mm SVL); (2) the broad neural arch that is not flattened dorsally (as 
in Bufo kelloggi); (3) the relatively large neural canal; (4) the round transverse processes; 
(5) the relatively short centrum (larger in Hyla). 

The fossil ilia are easily separated from those of anurans other than ranids and 
leptodactylids by the presence of a dorsal crest. The fossils can be separated from small 
Rana (ca. 33 and 39 mm SVL) by the dorsal crests being lower and the dorsal prom- 
inence being well-ossified without the porous texture of immature bone. They are 
referred to Leptodactylus melanonotus rather than male Hylactophryne augusti because 
of the well-developed dorsal prominence and small size. 

The scapulae of leptodactylids and ranids differ from those of other anurans by 
the glenoid surface being shifted medially, such that it parallels that acromial surface. 
The fossil scapula was referred to L. melanonotus rather than Rana because it is 



35 

relatively short and broad and is from a very small, mature individual (ca. 35 mm 
SVL). 

The fossil humeri were from individuals of about 33 mm and 37 mm SVL and 
were referred to L. melanonotus rather than other small anurans {Bufo kelloggi, Gas- 
trophryne olivacea, hylids) because of the exceptionally well-developed medial crest of 
males. The fossil radioulna is referred to L. melanonotus because of its very small size 
and stockiness. The tibiofibulae were referred to L. melanonotus because of their small 
size, straightness, and relative thickness in the center of the shaft. 

Leptodactylus melanonotus does not have a previous fossil record. It is a tiny frog 
in a tropical family found from central Sonora south into Central America. It is the 
northernmost species of Leptodactylus; Hylactophryne is the only other leptodactylid 
that occurs farther north. The nearest population of Leptodactylus melanonotus to the 
la Brisca site is southeast of Hermosillo. In southern Sonora, it lives in subtropical 
riparian habitats with perennial surface water. 

Family Microhylidae— Narrow-mouth Toads 
Gastrophryne cf. olivacea (Hallo well)— Great Plains Narrow-mouth Toad 

MarmW. -Sacral vertebrate (2; 1 1620), ilia (2R, L; 1 1619), humeri (2R, 2L; 11618). 

Comments. —The sacral vertebrae are small with the transverse processes expanded 
into wings, but not fused to the urostyle as in Scaphiopus. The sacral vertebra of Bufo 
kelloggi, another small fossorial "toad," is similar, but does not have the paired anterior 
cotyles. 

The ilia of Gastrophryne are very distinctive and differ from other small anurans 
including Acris, Bufo, Hyla and Pseudacris in the following combination of characters: 
(1) the head of ilium is at sharper angle with the shaft; (2) dorsal acetabular expansion 
is greatly reduced; (3) ventral acetabular expansion is moderately deep but very broad. 
The humeri are also very distinctive and exhibit the following characters: (1) well- 
ossified at a very small size; (2) the shaft is relatively straight; (3) the lateral epicondyle 
is very poorly developed; (4) the lateral crests poorly developed or absent; (5) the 
posterior surface opposite the ulnar condyle is rounded rather than flattened. 

Gastrophryne olivacea has been reported from the Sangamon Clear Creek local 
fauna, Denton County, Texas (Holman 1969a). This species is widespread in grassland 
habitats from the Great Plains to south-central Arizona; and south in subtropical 
lowlands through Sonora and Sinaloa to Nayarit (Nelson 1972). It probably lives near 
the la Brisca site today. 

Family Pelobatidae— Spadefoot Toads 
Scaphiopus couchi Baird— Couch's Spadefoot Toad 

Material.— At\as, vertebrae (2; 11624), ilia (2; 11623), scapula, radioulnae (2; 
11621), tibiofibula (11622). 

Scaphiopus species— Spadefoot Toad 

Material. —Ilia, radioulnae (5). 

Comments. —The atlas is referred to Scaphiopus because it has short broad cotyles 
(glenoid cavities of Gaup 1896) that are separated medially, and to S. couchi rather 
than 5". hammondi because the neural arch is relatively smooth and the posterior 
condyle is usually fused. The vertebrae are from individuals of 60-70 mm SVL and 
referred to Scaphiopus because the neural spine is absent; there is a well-developed 
spine on the posterior margin of the neural arch, and the condyles and cotyles are 
rounded and relatively small. Again, the condyles are fused as in S. couchi and not S. 
hammondi. 

The ilia are from individuals of 70-75 mm SVL and referred to Scaphiopus because 
the dorsal prominence is lacking. In 5". couchi the ventral acetabular expansion is 
broader where the shaft meets the acetabulum than it is in S. hammondi. The ilia 



36 

identified as Scaphiopus species are less complete, but are from individuals of 65-70 
mm SVL and could be from S. couchi as well. 

The fossil scapulae have the glenoid surface posterior to the acromial surface as 
in Bufo, Hylactophryne, and Scaphiopus, and not medial as in Rana. The anterior 
margin is curved into the "waist" as in Bufo and Scaphiopus, but not broad and angled 
as in Hylactophryne. In Scaphiopus, the articular surface is relatively small, and the 
acromial surface is relatively narrow. Scaphiopus couchi has a slender scapula that 
broadens and becomes better ossified with age. Scaphiopus hammondi has a broader 
scapula that is in some ways more similar to Bufo. The fossil was from an individual 
approximately 50 mm SVL. 

The fossil radioulnae are referred to S. couchi because: (1) of large size (ca. 75 mm 
SVL); (2) the "neck" is very broad with a well-developed crest on the ulna; (3) the 
olecranon and capitulum on the proximal end are relatively narrow. The radioulnae 
identified as Scaphiopus species are from smaller individuals and could represent S. 
couchi as well. 

The tibiofibulae oi Scaphiopus are distinctive because the tibia and fibula are fused 
into an arc on the proximal end where they contact the distal end of the femur, and 
the cartilaginous ends are simple and not ossified. In other anuran families, the tibia 
and fibula are separated more at the proximal end, and the cartilaginous articular 
surfaces are well-developed and can become well-ossified at maturity. The fossil is 
referred to S. couchi rather than S. hammondi because it is from a large individual 
and because the center portion of the bone is relatively thick. 

Scaphiopus cf. couchi was reported from Late Pleistocene or Holocene deposits of 
Bishop's Cap, (Brattstrom 1964) and Howell's Ridge Cave (Van Devender and Wor- 
thington 1977), New Mexico. Scaphiopus couchi was reported in the Late Wisconsin/ 
Early Holocene deposits in Deadman Cave, Pima County, Arizona (Mead et al. 1984). 
Its bones were found in an Early Holocene packrat midden dated at 8 1 50 ± 260 B.P. 
from near Wellton, Yuma County, Arizona (Van Devender and Mead 1978). Sca- 
phiopus couchi is widespread in many habitats from the southern Great Plains west to 
southwestern California and south to Baja California, Nayarit, and central Mexico 
(Wasserman 1970). It probably lives at the la Brisca site today. 

Family Ranidae— Frogs 
Rana ""pipiens"" Shreber-Complex— Leopard Frog 

Material— M2i\\\\diQ (2R, 2L; 11626), dentaries (2R, L; 11627), ethmoid, trunk 
vertebrae (3; 1 1632), sacral vertebrae (5; 1 1633), ilia (17; 1 1631), urostyles (7), fused 
pelvis, ischia (2), coracoid, scapulae (6R, 2L; 1 1628), humeri (2R, 2L; 1 1629), radioul- 
nae (4R, 2L; 11 630), tibiofibulae (2). 

Comments. —The fossil maxillae are referred to R. ''pipiens" because: (1) relatively 
large teeth (smaller in Hyla) are present (lacking in Bufo); (2) moderate size; (3) relatively 
smooth surface (rugose in Pternohyla). The dentary is referred to R. ''pipiens" because 
the flange on the ventral edge of Meckel's groove posterior to the coronoid process is 
broad and not indented dorsally. The fossil ethmoid is thin and high compared to Bufo 
and Hylactophryne. The fossil vertebrae have broad, oval cotyles and condyles and the 
prezygapophysial surfaces are strongly angled dorsally. The sacral vertebrae are referred 
to R. ""pipiens'' because they possess an anterior condyle rather than a cotyle (Bufo, 
Hylactophyrne, Hyla, Leptodactylus, Pternohyla); they are not fused to the urostyle 
(Scaphiopus), and the transverse accessory processes are not expanded distally into 
"wings" (Scaphiopus, Gastrophryne, Bufo kelloggi). The ilia are referred to R. ""pipiens"" 
because: (1) the dorsal crest is well-developed; (2) the dorsal prominence is at a sharper 
angle than in leptodactylids (Eleutherodactylus, Hylactophryne, Leptodactylus); (3) the 
dorsal acetabular expansion is slightly higher than the ventral acetabuler expansion. 
The urostyles are referred to R. ""pipiens'' because of the (1) high dorsal coccygial spine 
along most of the body; (2) large oval vertebral canal above oval paired anterior cotyles 
(glenoid cavities); (3) relatively little space between the cotyles and the anterior end of 
the coccygial spine. 



37 

The fossil scapulae are referred to R. '"pipiens"" because: (1) the glenoid portion is 
shifted medially so that it parallels the acromial portion; (2) the size is large compared 
to Leptodactylus melanonotus. The fossil humeri are referred to R. '"pipiens"' because 
of a narrow shaft, and a small distal end of the lateral epicondyle. The fossil radioulnae 
are referred to R. ""pipiens" rather than R. larahumare {TarahumaTa Frog). Ranapipiens 
{sensu lato) has been segregated into a complex of closely related species that inhabit 
virtually all aquatic habitats in North America. No attempt was made to distinguish 
the fossils from the southwestern species in this complex {R. berlandieri, R. blairi. R. 
chiricahuensis, R. magnaocularis, R. pipiens, R. yavapaiensis; see discussion and ref- 
erences in Platz and Frost 1984). Leopard Frogs are common in the la Brisca area today 
(UAZ 42422). Rana ""pipiens"" is common in many paleofaunas that range in age from 
at least the Late Miocene to many southwestern Late Pleistocene faunas (Holman 
1969a). The only previous fossil record in Mexico is from a Rancholabrean cave deposit 
in Tamaulipas (Holman 1969c). 

Class Reptilia— Reptiles 

Order Testudines — Turtles 

Family Emydidae— Pond Turtles 

of. Terrapene— Box Turtle 

Material.— L. peripheral. 

Comments. —The fossil is the anterior half of the eighth or ninth left peripheral 
that is similar to some of the robust Rancholabrean box turtles (e.g., Terrapene Carolina 
putnami). The bone is very thick and flared, with a well-developed dorsal trough, or 
"rain gutter." The fossil differs from T. ornata (Ornate Box Turtle) in its thickness and 
in that the sulci for the marginal scutes are not angled. 

Although robust T. Carolina have a rich late Pleistocene fossil record east of the 
Continental Divide (Milstead 1967, 1969), the only fossil box turtles from farther west 
are early Blancan (late Pliocene) Terrapene species (cf T. ornata) and Rancholabrean 
T. ornata from Arizona (Moodie and Van Devender 1978). Terrapene ornata is found 
from the Great Plains to southeastern Arizona and into north-central Sonora. Terrapene 
nelsoni (Sonoran Spotted Box Turtle) is a Mexican species in the T. ornata group that 
barely enters southern Sonora from the south in tropical deciduous forest (Milstead 
and Tinkle 1967). Male T nelsoni can have flared peripherals. Rhinoclemmys pul- 
cherrima (Central American Wood Turtle) is a terrestrial and semi-aquatic neotropical 
emydid with a well-developed "rain gutter" that also enters southern Sonora. 

Pseudemys scripta Schoepff'— Yaqui Slider 

Material. —Nuchal (10156, cast; Fig. 8), neural, pleural fragments (8; 10143, 10420- 
10421, 15445), peripherals (6; 10144, 11625), ilium, hyoplastron (15444). 

Comments.— The la Brisca fossils are from a large emydine turtle and have the 
strong ridging characteristic o^ Pseudemys scripta. The lateral edges of the first vertebral 
scute are concave medially on the nuchal bone (Fig. 8). The anterolateral comers of 
this scute contact the lateral edge of the nuchal bones; the comers are more often well 
within the nuchal bone. We have not tried to refer the specimens to a modem or fossil 
subspecies off. scripta, although the nuchal is not as thick and rugose as late Pleistocene 
specimens from east of the Continental Divide. An adult P. scripta yaqiiia collected 
from the Saracachi Cienega (Fig. 2) is fairly small for the species (210 mm carapace 
length) and has a strongly flattened shell. Larger individuals, including an old melanistic 
adult, have been observed in the cienega. The maximum adult size of this turtle is 
larger and the shells are more domed in the Rio Yaqui and the Rio Mayo. The fossil 
pleurals from Rancho la Brisca are from individuals of about 275 mm carapace length. 
One specimen has a fairly uniform thickness of 4.7 mm and is relatively flat, suggesting 
a flattened shell. Domed shells have pleurals that are more curved, and differentially 
thickened medially at the articular surface with the vertebral bones. The pleurals are 
somewhat thicker than modem shells of similar-sized individuals. The hyoplastron is 
from a small juvenile with large unfused areas between the bones of the plastron. 



38 




mm 

Figure 8. Nuchal bone (UALP 101 56, cast) of Pseudemys scripta (Yaqui Slider). 

Pseudemys scripta is a common fossil in deposits of Pliocene to late Pleistocene 
age in the eastern and central United States. The la Brisca specimen is the first Ran- 
cholabrean record west of the Continental Divide. Lindsay (1984) reported Chrysemys 
{=Pseudemys) from Irvingtonian deposits at El Golfo, Sonora, at the mouth of the 
Colorado River (C. A. Shaw, personal communication 1985). Presently, P. scripta is a 
sporadic inhabitant of the rivers of Sonora as far north as the Rio Bavispe drainage 
(UAZ 39965) in northeastern Sonora. 

Family Kinostemidae— Mud Turtles 
Kinosternon flavescens Agassiz— Yellow Mud Turtle 

Material. — Hypoplastron. 

Comments.— The fossil Kinosternon material from la Brisca was identified by John 
B. Iverson, Earlham College. A single hypoplastron was referred to K. flavescens rather 
than to K. sonoriense because the sulcus for the femoral scute is parallel to the posterior 
margin. 

Fossils of Kinosternon flavescens have been reported from late Hemphillian and 
Blancan deposits in Nebraska (Holman 1972), Kansas (Fichter 1 969), and Texas (Rogers 
1976). Kinosternon arizonense, described by Gilmore (1922) from the Blancan Benson 
Fauna, Cochise County, Arizona, is now considered a subspecies of K. flavescens (Iver- 
son 1919a). Kinosternon flavescens was in the Folsom cultural levels at the Lubbock 
Lake Site, Lubbock County, Texas, at about 1 1 000 to 10 000 years ago (Johnson 1974). 
The la Brisca specimen is the only Rancholabrean record from west of the Continental 
Divide and Mexico. 

Kinosternon flavescens presently ranges from Illinois south into northeastern Mex- 
ico and southwest to Arizona and Sonora. K. f. arizonense is locally common in a 
number of areas between Caborca and Hermosillo (J. Iverson, personal communication 
1982). It has not been collected near la Brisca. 

Kinosternon sonoriense LeConte— Sonoran Mud Turtle 

Ma/ma/. -Cervical vertebra (10422), nuchals (2; 10428), neurals(4; 10145, 10429), 
pygal (10423), 8th and 9th right peripherals (10424-10425), epiplastral fragments (12; 



39 




mm 

Figure 9. Left and right hypoplastra (UALP 10147) of Kinosternon sonoriense (Sonoran Mud Turtle). 



10146, 10426), hyoplastra(8; 10147, 10427, 1 1 137), hypoplastra (10148, 11138; Fig. 
9), xiphiplastra (10149). 



Kinosternon species— Mud Turtle 

Material— T>QnX2ivy, humeri (2), femora (3), ilium, ischia (3), neurals (5), supra- 
pygal, pleural fragments (71; 15435, 15439-15440), peripherals (61; 15441-15443), 
epiplastra (3), hyoplastra (10; 15437), hypoplastra (7), xiphiplastra (2; 15436). 

Comments. —Most of the Kinosternon specimens identified to species are referred 
to K. sonoriense. The sutures on the right eighth peripheral bone show that the ninth 
marginal scute is not raised as in K. flavescens. The most common fossils at the la 
Brisca site are Kinosternon species; most of these are probably from K. sonoriense. 

Kinosternon sonoriense is a common aquatic turtle in southern Arizona, Chihua- 
hua, and northern Sonora (Iverson 1976); it is replaced by K. alamosae and K. integrum 
(Alamos and Sinaloan Mud Turtles) in southern Sonora. Numerous specimens have 
been collected from Sonora, including one from 5 km below Cucurpe in the Rio San 
Miguel (UAZ 36509), and a series from the Saracachi Cienega (TRV 2716; Fig. 2). It 
occurs in the stream below the la Brisca site today. Kinosternon sonoriense has no 
previous fossil record. 



Order Squamata— Lizards and Snakes 

Suborder Sauria— Lizards 

Family Iquanidae— Iguanid Lizards 

cf Callisaurus draconoides Blainville— Zebra-tailed Lizard 

Material. —Anterior half of frontal. 

Comments. —This incomplete specimen resembles Callisaurus draconoides in (1) 
size; (2) the deeply excavated ventral surface; (3) the ventrolateral edges having heavy 
angular surfaces; (4) the relatively narrow anterior end and a relatively broad interorbital 
width. Sceloporus (several species) and Holbrookia texana (Greater Earless Lizard) are 
broader to the anterior. The ventral surface of the frontal is relatively shallowly ex- 
cavated in Sceloporus and Holbrookia maculata (Lesser Earless Lizard). The interorbital 
portion of the frontal in H. maculata is very thin. The only previous fossil record for 
Callisaurus draconoides is from Late Wisconsin/Early Holocene deposits in Deadman 
Cave, Santa Catalina Mountains, Pima County, Arizona (Mead et al. 1984). This 
cursorial lizard is a Sonoran Desert species most often found in desertscrub and thorn- 
scrub habitats. In the la Brisca area, it follows sandy washes up into oak woodland. 



40 



Sceloporus cf. clarkii Baird and Girard— Clark's Spiny Lizard 



Material. — Dentary, parietal, jugal. 

Comments. —The dentary is from a large lizard in the Sceloporus spinosus group 
based on (1) size; (2) tricuspid tooth crowns; (3) transversely expanded tooth bases; (4) 
Meckel's canal closed, but not fused; (5) dentary relatively deep below Meckel's canal. 
The teeth are more slender than 5. magister (Desert Spiny Lizard) and relatively larger 
than the large subspecies of S. undulatus elongatus (Northern Plateau Lizard), or S. 
occidentalis (Western Fence Lizard). The parietal and jugal also compare well with S. 
clarkii, but are less diagnostic. Sceloporus cf. clarkii was reported from Late Wisconsin/ 
Early Holocene deposits in Deadman Cave, Santa Catalina Mountains, Pima County, 
Arizona (Mead et al. 1 984). Sceloporus clarkii lives in habitats ranging from subtropical 
thomscrub in Sinaloa and southern Sonora to oak woodland in the Sierra Madre and 
in southern Arizona. It occurs today near the fossil site. 

Suborder Serpentes— Snakes 

Family Colubridae— Colubrid Snakes 

Hypsiglena torquata (Giinther)— Night Snake 

Material. —Vertebra. 

Comments.— This small colubrid was identified as Hypsiglena torquata on the 
following characters: (1) small size; (2) condyle and cotyle small and round; (3) neural 
spine moderately high; (4) accessory processes short, pointed, and oriented anteriorly; 
(5) relatively short vertebrae, and zygosphene curved down from the anterior. Sonora 
semiannualata (Ground Snake) and Chionactis occipitalis (Banded Sand Snake) have 
lower neural spines and more elongate vertebrae. Chilomeniscus cinctus (Shovel-nosed 
Snake) has longer accessory processes that are more perpendicular to the long axis of 
the vertebrae. Hypsiglena torquata was common in late Pleistocene and Holocene 
sediments in Howell's Ridge Cave, southwestern New Mexico (Van Devender and 
Worthington 1977). Hypsiglena torquata was reported from the Late Wisconsin/Early 
Holocene deposits in Deadman Cave, Pima County, Arizona (Mead et al. 1984). It has 
been found in eight packrat middens of Late Wisconsin and Early Holocene age from 
the Grand Canyon south into the Sonoran Desert in Arizona and California (Van 
Devender, Phillips, and Mead 1977; Van Devender and Mead 1978; Mead and Phillips 
1981). Hypsiglena torquata is widely distibuted in habitats ranging from woods and 
desertscrub to pine forests (Van Devender and Lowe 1977). 

Masticophis cf. mentovarius (Dumeril, Bibron and Dumeril)— Tropical Whipsnake 

Material. -Middorsal vertebrae (20; 10152, 10430, 11139; Fig. 10), cervical ver- 
tebrae (5; 11634). 

Comments. —Most of these vertebrae are from a very large colubrid snake; e.g., 
centrum lengths of 7.0-8.3 mm (x = 8.0 mm, « = 16) for mid-dorsal vertebrae (Fig. 
10) and 6.4-6.7 mm (x = 6.5 mm, n = 4) for cervical vertebrae. Sonoran colubrids 
reaching this size include Drymarchon corais (Indigo Snake), Masticophis (several 
species), and Pituophis melanoleucus (Bullsnake). Spilotes pullatus (Tropical Ratsnake) 
is a large colubrid that occurs farther south in Mexico. The la Brisca fossils differ from 
those of Pituophis melanoleucus and Spilotes pullatus in being more elongate and the 
cotyle and condyle are round and much smaller. The average centrum length/neural 
arch width (cl/naw) ratio for the large la Brisca vertebrae is 1.24 (range 1.21-2.32, n = 
15) for mid-dorsal vertebrae. A small vertebrae (cl = 6.36 mm) has a cl/naw ratio of 
1.41. This is the upper range for Drymarchon corais (Auffenberg 1963) and within the 
range o^ Masticophis. A sample of 20 middorsal vertebrae averaged 1.49 (range 1.45- 
1.53) in a M.flagellum (Red Racer, Coachwhip) of 1076 mm SVL (TRV 433: Mexico: 
Sonora: 4.3 km E Navojoa) and 1 .30 (range 1 .23-1 .42) in a specimen of M mentovarius 
(Tropical Whipsnake) of 1 570 mm SVL (TRV 1735: Costa Rica: Guanacaste Province). 
The la Brisca specimens are referred to Masticophis rather than Drymarchon corais 



41 




mm 



^^■44^v 



Figure 10. Vertebra (dorsal view) of Masticophis cf. mentovarius (Tropical Whipsnake). 

because: (1) the neural spine is much lower and longer and lacks the bevelled anterior 
edge (ibid); (2) the accessory processes are longer and oblique to the anterior as viewed 
from above (they are lateral in D. corais); (3) the cotyle and condyle are round and 
relatively smaller. The la Brisca specimens are from a snake of about 1500 mm SVL, 
which is close to the maximum sizes for several species of Masticophis {M. flagellum, 
M. bilineatus, and M. taeniatus; Wilson 1970). Masticophis mentovarius reaches 1886 
mm SVL (Johnson 1977, 1982). Although the record size for the northern subspecies 
M. m. stholatus is only 1 120 mm SVL (Johnson 1977), animals of at least 1600-1700 
mm SVL have been observed in Sonora (H. Lawlor, personal communication). The 
vertebrae most closely resemble a large M. mentovarius. 

Although vertebrae o{ Masticophis and Coluber are common late Pleistocene fossils 
(Auffenberg 1963, Brattstrom 1954, 1958, Hill 1971, Holman 1969a, Van Devender 
and Mead 1978), the only previous fossil record for M. mentovarius is from Holocene 
Cave deposits in Yucatan, Mexico (Langebartel 1953). 

Masticophis flagellum and M. bilineatus (Sonoran Whipsnake) probably live at la 
Brisca today. Masticophis m. striolatus has been collected at Santa Ana de Yecora, 
Sonora (UAZ 40078; 270 km SSE la Brisca) and has been observed on the Rio Yaqui 
east of Hermosillo (240 km SSE la Brisca). 

Salvadora species— Patch-nosed Snake 

Material. —Vertebra. 

Comments.— The elongate, medium-sized vertebra is from Salvadora. The con- 
dyle, cotyle, and neural canal are relatively smaller than in similar-sized Masticophis 
or Coluber, but larger than in Opheodrys (Green Snake), which also has somewhat 
longer accessory processes. The vertebrae of Salvadora hexalepsis (Desert Patch-nosed 
Snake) and S. grahamiae (Mountain Patch-nosed Snake) are very similar. Late Wis- 
consin and Holocene fossils of Salvadora species are known from Dry Cave, Eddy 
County (Holman 1970) and Howell's Ridge Cave, Grant County (Van Devender and 
Worthington 1977), New Mexico, and Deadman Cave, Pima County, Arizona (Mead 
et al. 1984). Patch-nosed Snakes live in many habitats from desertscrub to Mexican 
pine-oak woodland. Salvadora hexalepsis probably lives near la Brisca today. 



Thamnophis cf. cyrtopsis (Kennicott)— Black-necked Gartersnake 

Material. —Vertebrae (2; 11141). 

Comments. —The small natricine vertebrae are from a species of Thamnophis, and 
came from individuals with SVLs of about 350 mm and 570 mm. The vertebrae (and 



42 



often the external morphology) of T. cyrtopsis and T. eques (Mexican Gartersnake) are 
very similar, and apparently differ only in a more slender hypopophysis in T. cyrtopsis. 
Thamnophis marcianus (Checkered Gartersnake) has shorter vertebrae, shorter acces- 
sory processes, and broad hypopophyses. Both vertebrae compared best with T. cyr- 
topsis. Thamnophis cyrtopsis is a snake of rocky canyons from the upper edge of the 
desertscrub into pine forest in the Sierra Madre and southern Arizona. It is common 
in the la Brisca area today (UAZ 42359). The only previous fossil record for T. cyrtopsis 
is from Late Wisconsin and Early Holocene deposits in Howell's Ridge Cave, Hidalgo 
County, New Mexico (Van Devender and Worthington 1977). 

Family Crotalidae— Rattlesnakes 
Crotalus atrox Baird and Girard— Western Diamondback Rattlesnake 

Material. —Vertebrae (2; 1 1 140), centrum. 

Comments.— 'WiQ vertebrae are from a very large rattlesnake with (1) a broad 
zygosphene; (2) very large cotyle and condyle; (3) a high neural arch as viewed anteriorly. 
Measurements of the largest vertebra are cl = 7.33 mm, naw = 8.64 mm, cl/naw = 
0.85. Crotalus basiliscus (Mexican Green Rattlesnake) has a narrower zygosphene, 
whereas C. molossus (Black-tailed Rattlesnake) has a flattened neural arch. 

Late Wisconsin records for Crotalus atrox are from Friesenhahn and Miller's 
Caves, central Texas (Holman \969a), and Dry Cave, southeastern New Mexico (Hol- 
man 1970). Crotalus atrox was reported from Late Wisconsin/Early Holocene deposits 
in Deadman Cave, Pima County, Arizona (Mead et al. 1984). It was found in an Early 
Holocene packrat midden dated at 10 330 ± 330 B.P. in the Whipple Mountains, 
southeastern California (Van Devender and Mead 1978). Crotalus atrox is widespread 
in many habitats below woodland and forest from the Texas Gulf Coast west to south- 
eastern California and south into Mexico. Crotalus molossus is the common rattlesnake 
at la Brisca today, although C. atrox is probably not far away in more xeric habitats. 

Class Aves— Birds 

Order Anseriformes— Water Fowl 

Family Anatidae— Ducks 

Anas cf crecca Linnaeus— Green- winged Teal 

Material. — Coracoid, missing the proximal head. 

Comments. —On the basis of its very small size, the coracoid seems best referred 
to the widespread small Green-winged Teal. Anas carolinensis is now considered to be 
conspecific with the Old World A. crecca. The only previous record for the Pleistocene 
of Mexico is from Jiminez Cave, Chihuahua (Brodkorb 1 964, Messing in press). 

Order Falconiformes— Eagles, Hawks, and Vultures 

Family Accipitridae— Hawks, Kites, Harriers, and Eagles 

cf Spizaetos — Hawk-eagle 

Material. —Distal half of metacarpal 2, lacking articular surface. 

Comments. —This specimen was identified by R. McKenzie as being near the 
Rancholabrean Spizaetos grinnelli (GvinnQVs Hawk-eagle), but somewhat smaller. Wing 
elements of the two living New World tropical species (S. ornatus and S. tyrannus) 
were not available for comparison. Spizaetos grinnelli has been reported from Carpin- 
teria and Rancho la Brea in California, and San Josecito Cave in Nuevo Leon, Mexico 
(Brodkorb 1964). 

tSpecies indeterminate 

Material. —Right digit 2, phalanx 2. 

Comments. —The fossil is the size of an eagle (Aquila), but has some characters 
different from that genus. A reference specimen of Haliaeetus leucocephalus (Bald Eagle) 
was not available for comparison. It does not resemble Cathartes (Cathartid Vultures) 
or Mycteria (Storks), which Ligon (1967) has shown to be more closely related to each 



43 






20i 



QJ 



- mm 



Figure 1 1 . Owl left tarsometatarsi, dorsal aspect: modem Strix nebulosa (Great Gray Owl) on left; Rancho 
la Brisca S. brea in center; holotype of Strix brea (La Brea Owl) from Rancho la Brea (LACM E9379) on 
right. 



Other than to true falconiforms. In the Pleistocene of North America there were nu- 
merous eagles and eagle-like vultures (Howard 1932), but their distal-most wing ele- 
ments are undescribed. 



Order Galliformes— Gallinaceous Birds 

Family Phasianidae— Pheasants, Quails, etc. 

Meleagris gallopavo Linnaeus— Common Turkey 

Material. —Distal end of ulna. 

Comments. —The fossil was included as a female M. gallopavo in Rea's (1980) 
summary of late Pleistocene and Holocene turkeys in the Southwest. The only other 
late Pleistocene record of M. gallopavo from west of the Continental Divide is from 
Arizpe, ca. 25 km SE of la Brisca. The extinct M. crassipes was widespread in the late 
Quaternary of the Southwest. Historically, M. gallopavo probably lived near la Brisca, 
although M. g. merriami (Merriam's Turkey) in Arizona and New Mexico appears to 
represent feral introductions from prehistoric domestic animals (Rea 1980). 

Order Strigiformes— Owls 

Family Strigidae — Typical Owls 

'\ Strix brea Howard— La Brea Owl 

Material. —Left tarsometatarsus missing proximal end (10157, cast; Fig. 1 1). 

Comments.— The tarsometatarsus is from an owl the size of a male Bubo virgi- 
nianus (Great-homed Owl). Strix is distinguished from Bubo by ( 1 ) more parallel lateral 
edges of the shaft; (2) the distal calcaneal ridge not converging with the internal ridge 
of the shaft. The extinct Strix brea is distinguished from the living species S. nebulosa, 
S. occidentalis, and S. varia by a more prominent tubercle for the attachment of the 
M. tibialis anticus being placed higher on the shaft (see Howard 1933). The la Brisca 
specimen was compared directly with the type and type series (n = 9) of S. brea at 
LACM (Fig. 11). The living S. nebulosa (Great Gray Owl) of northern hemisphere 
boreal forests has a shorter, stouter tarsometatarsus. Measurements of the la Brisca 
fossil are: proximal end of trochlea for digit 3 to distal end of tubercle for M. tibialis 



44 



amicus = 37.9 mm; width across trochlea = 15.99 mm. Strix brea has been found 
previously only in California at the Rancho la Brea (ibid.) and Carpinteria (R. Mc- 
Kenzie, personal communication 1978) asphalt deposits. 

Order Passeriformes— Perching Birds 
Family Fringillidae, Emberizinae— New World Sparrows, Finches, etc. 

Genus and species indeterminate 

Material. —Right coracoid missing base (1 1 142). 

Comments. —The coracoid is indistinguishable from Junco Ouncos) and Zono- 
trichia (sparrows). Elsewhere, an indeterminant Emberizinae was reported from the 
Late Wisconsin/Early Holocene deposits in Deadman Cave, Pima County, Arizona 
(Mead et al. 1984). Several species in these genera occur in the la Brisca area as winter 
migrants. 

Family Icteridae— Meadowlarks, Blackbirds, Orioles 
Agelaius phoeniceus Linnaeus— Red- winged Blackbird 

Material. —Right humerus missing head and ectepicondylar process (11161, cast). 

Comments. —The specimen was compared with Sturnella (Meadowlarks, 2 species), 
Dolichonyx oryzivorus (Bobolink), Xanthocephalus xanthocephalus (Yellow-headed 
Blackbird), Euphagus (Blackbirds, 2 species), Molothrus (Cowbirds, 3 species), Quis- 
calus (Crackles, 2 species). Icterus (Orioles, 2 species), Cassiculus (Mexican Cacique), 
Cacicus (Cacique), and Cardinalis cardinalis (Cardinal). This species is well-represented 
in late Pleistocene sites (Brodkorb 1978), and occurs today in stream and cienega 
habitats in the la Brisca area. 

Class Mammalia— Mammals 

Order Camivora— Carnivores 

Family Procyonidae— Raccoons, Coatis and Ringtails 

Bassaricus species— Ringtail 

Material.— KV. 

Comments. —The tooth is a premolariform incisor which closely resembles that 
of the extant Bassariscus astutus in having the crown offset with the root to the 
posterior, and the internal face spathulate. In Urocyon and Vulpes, the tooth is more 
caniniform and not spathulate medially. The incisor of Must el a is similar, but blunter, 
less spathulate, and with the crown centered over the root. 

Bassariscus sonoitensis is an extinct Wisconsin Ringtail known only from Papago 
Spring Cave, Arizona, and San Josecito Cave, Nuevo Leon, northeastern Mexico; 
Bassariscus astutus is known from 1 4 Late Wisconsinin faunas from California, Nevada, 
New Mexico, and Texas (Kurten and Anderson 1980). Several additional records from 
Late Wisconsin/Early Holocene cave deposits in the Grand Canyon and Santa Catalina 
Mountains of Arizona have been reported (Mead 1981, Mead et al. 1984). 

Order Artiodactyla— Even-toed Ungulates 

Family Camelidae— Camels and Llamas 

"fCamelops species— Camel 

Ma/er/a/.— Navicular (10153, cast; Fig. 12). 

Comments. —The navicular is not fused with the cuboid and is from a large animal 
(Fig. 1 1). The bone does not resemble those of Bison, Equus, or any of the large cervids. 
The specimen is very similar to the navicular of a modem Camelus dromedarius 
(Dromedary) from Pakistan. It appears to be close to Camelops hesternus (Yesterday's 
Camel) in size, and larger than the extinct llamas (Hemiauchenia and Paleolama). 
Camelops species was reported from Irvingtonian deposits at El Golfo, Sonora (Lindsay 
1984). Camelops species is known from a number of Rancholabrean localities in Ar- 
izona (Lindsay and Tessman 1974). Camelops hesternus was the common, widespread 



45 




20 
I 1 1 



mm 

Figure 12. Navicular of Camelops species (UALP 10153, cast). 



camel in the late Pleistocene of the western United States. It has been reported from 
several localities in Arizona, including a packrat midden dated at 13 820 ± 220 B.P. 
from Vulture Cave in the western Grand Canyon (Mead and Phillips 1981). 

Family Cervidae— Deer 
Odocoileus hemionus Rafinesque— Mule Deer 

Material. —Left antler (10444, cast; anterior half of RM, or RM2). 

Comments.— This antler is referred to Odocoileus hemionus rather than O. vir- 
ginianus (White-tailed Deer) because: (1) the shaft is only moderately curved anteriorly 
and laterally; (2) the two tines at the first main fork are not greatly different in size 
(anterior tine = 17.4 x 14.7 mm, posterior tine = 23.4 x 18.3 mm). The basal bur is 
thickest to the anterior (37.3 x 32.1 mm). A small medial tine (38.0 mm long, 16.0 x 
9.1 mm cross-section) is 37.4 mm above the bur. The base of the main fork is 134 
mm above the bur. The antler is broken just above the main fork. The shaft below the 
fork is flattened (17.8 x 16.6 mm). The shaft above the fork is also flattened, but may 
be crushed. The molar fragment could be from O. hemionus as well. 

Odocoileus is first recorded in North America and Arizona in the Blancan Land 
Mammal Age (Lindsay and Tessman 1974). Odocoileus species was reported from 
Irvingtonian deposits at El Golfo, Sonora (Lindsay 1984). Odocoileus hemionus has 
been reported from 1 5 Irvingtonian and Rancholabrean sites from Arkansas to British 
Columbia and California (Kurten and Anderson 1980). This is the first Pleistocene 
record for Mule Deer from Mexico. Odocoileus virginianus presently lives in the la 
Brisca area, while O. hemionus occurs at lower elevations to the south and west. 

Family Antilocapridae— Pronghom Antelope 
Capromeryx cf. minor Taylor— La Brea Pronghorn 

Material. —hY*^ (15446, cast). 

Comments.— Th\s tiny molariform premolar is similar in size to Capromeryx 
minor {= Breameryx minor, Kurten and Anderson 1980) based on comparisons with 
material in the LACM collections by George T. Jefferson. Capromeryx minor stood 
only 560 mm at the shoulder and weighed about 1 kg. Previous Rancholabrean records 
for C. minor arc from Ingleside on the Texas Gulf Coast, Blackwater Draw, New Mexico, 



46 




1-20 



Figure 13. Molar of Bison species (UALP 10154, cast). 



and McKittrick, Rancho La Brea, and Schuiling Cave, California (ibid.). Capromeryx 
mexicana (Mexican Pronghom) from the late Pleistocene of the Mexican Plateau was 
about the same size as C. minor. The only record of the genus for Arizona is Capromeryx 
gidleyi from the Irvingtonian Curtis Ranch fauna in the San Pedro Valley, Cochise 
County (Lindsay and Tessman 1974, Johnson et al. 1975). 

^Tetrameryx species— Four-homed Antelope 

Material. — LM' (1 1 162, cast). 

Comments.— Tht molar fragment was compared to the LACM collections by 
McKenzie and Jefferson and referred to Tetrameryx species on size and morphology. 
The fossil is from an animal smaller than Oreamnos (Mountain Goat), Ovis canadensis 
(Bighorn Sheep), and Odocoileus (Deer), but larger than Antilocapra americana (Prong- 
hom), Stockoceros, and Capromeryx (extinct pronghoms). The enamel pattern of the 
fossil was similar to that of the antilocaprids, but not to the other artiodactyls examined. 
Tetrameryx has five Irvingtonian and Rancholabrean species known from Texas or 
central Mexico (Kurten and Anderson 1980). Tetrameryx species was reported from 
Irvingtonian deposits at El Golfo, Sonora (Lindsay 1984), and from Rancholabrean 
deposits at Tule Springs, Nevada (Mawby 1967). 



Family Bovidae— Bovids 
"f Bison species— Bison 

Material. —Lower molars (2, R, LM; or M2; 10154, cast; Fig. 13), ungual phalanx. 

Comments. —These teeth are from a large Bison, but species determination is not 
possible. Fossil Bison have been reported from a number of Rancholabrean sites in 
Arizona including Papago Springs and Ventana Caves (Lindsay and Tessman 1974). 
This is the first published report of Bison for Sonora, although it has been collected 
from several other sites (R. S. White, personal communication). 



47 

Order Perissodactyla— Odd-toed Ungulates 

Family Equidae — Horses 

fEguus cf. tau Owen — Pygmy Onager 

Material.— LV'~, LM'°^- (15447, cast), lower molar fragment (10155, cast), 
RP3or4 (15447, cast), lower molar fragment, second phalanx, thoracic vertebra. 

Comments. —These remains are from a very small species of horse. The upper 
molar is worn nearly to the roots and was from a very old individual. The tooth is 
shorter on the anterior-posterior axis than the transverse axis (21.3 x 25.4 mm). Equus 
tau is characterized by a very short tooth row that was usually less than 1 20 mm in 
length (Kurten and Anderson 1980). Measurements for the lower premolar from la 
Brisca are 29.6 mm x 16.2 mm. Most of the la Brisca fossils could be from E. tau. 
although some of them could be from the slightly larger E. conversidens (Mexican 
Horse). 

Equus tau was the smallest species of New World onagers, or stilt-legged horses 
(subgenus Hemionus), as well as the smallest American Equus (ibid.). It is known from 
Irvingtonian and Rancholabrean deposits from the Valley of Mexico to Oklahoma, 
Florida, Texas, and Arizona (ibid.). Equus cf. conversidens was reported from Irving- 
tonian deposits at El Golfo, Sonora (Lindsay 1984). Both E. tau and E. conversidens 
were reported from Rancholabrean deposits in Papago Springs Cave, south-central 
Arizona (Skinner 1942). 

f Equus species— Horse 

Material.— R. femur. 

Comments. —The femur is apparently from an immature individual of a large 
horse because it is similar in size to the femur of an adult E. asinus (Burro), but the 
epiphyses on both ends are not fused. Remains of large horses have been reported in 
a number of Rancholabrean deposits in Arizona (Lindsay and Tessman 1974). Equus 
occidentalis (Western Horse) was common in the latest Rancholabrean deposits in 
Ventana Cave on the Papago Indian Reservation, southwestern Arizona (Haury 1975). 

Order Proboscidea— Elephants, Mastodons, Gomphotheres 

Family Elephantidae— Mammoths and Elephants 

fMammuthus species— Mammoth 

Material.— R. pisiform, thoracic vertebra. 

Comments. —The vertebra is identified as Mammuthus species on the basis of its 
large size and its rounded, rather than sub-triangular shape as in Mammut. The pisiform 
has the more elongate shape of Mammuthus (Olsen 1972). Additional proboscidean 
remains not identifiable to genus include tusk and skull fragments, a fragment of a 
humerus, and several partial ribs. Mammuthus remains have been reported from many 
sites in Arizona (Saunders 1970) and are known from over 25 unpublished localities 
in Sonora (R. S. White, personal communication 1975). Mammuthus imperator (Im- 
perial Mammoth) was reported from Irvingtonian deposits at El Golfo, Sonora (Lindsay 
1984). Mammuthus sonorensis (Sonoran Mammoth) was described from Irvingtonian 
or Rancholabrean deposits from Arizpe, Sonora (Lindsay 1984), but has been consid- 
ered a synonym of M. columbi (Columbian Mammoth; Kurten and Anderson 1980). 
Mammuthus columbi was the common Rancholabrean elephant of the southwestern 
United States, although there is some question of its distinctness from M. jeffersoni 
(Jefferson's Mammoth; Kurten and Anderson 1980). 

Order Rodentia— Rodents 

Family Heteromyidae— Kangaroo Rats and Pocket Mice 

Dipodomys species— Kangaroo Rat 

Material. — LM2. 

Comments. —The tooth is from a species of Dipodomys in the size range of D. 
merriami (Merriam's Kangaroo Rat) and D. ordi (Ord's Kangaroo Rat). Teeth of Kan- 



48 

garoo rats are common in fossil packrat middens from the Mohave Desert (Van De- 
vender et al. 1977). Dipodomys species and D. merriami were identified from three 
Late Wisconsin and six Early Holocene packrat middens from the Sonoran Desert in 
southwestern Arizona and adjacent California (Mead et al. 1983). Dipodomys species 
and Dipodomys cf. ordi have been identified in Late Wisconsin sediments from Smith 
Creek Cave, Snake Range, eastern Nevada (Mead et al. 1982). Dipodomys merriami 
and D. ordi are widespread in desertscrub and desert-grassland habitats and probably 
occur near la Brisca today. 



Family Cricetidae— Mice, Rats, Lemmings, and Voles 
Neotoma species— Packrat 

Material. — LM2. 

Comments. —This tooth is referred to Neotoma by being relatively large and high- 
crowned among rodents. The lophs are rounded (as in A^. albigula, N. lepida, N. mi- 
cropus) and not prismatic (as in A", cinerea, N. mexicana, N. stephensi; Harris 1984). 
Neotoma albigula (White-throated Packrat) was reported from Late Wisconsin/Early 
Holocene deposits in Deadman Cave, Pima County, Arizona (Mead et al. 1984). Teeth 
of Neotoma are common late Pleistocene fossils in ancient packrat middens in Arizona 
and California (Van Devender et al. 1977; Mead et al. 1983). Packrats live in virtually 
all habitats from desertscrub at sea level to montane boreal forests over 3000 m ele- 
vation. Neotoma albigula presently lives at la Brisca. 

Onychomys species— Grasshopper Mouse 

Material— KM ^. 

Comments. —The teeth of Onychomys can be separated from those of similar- 
sized Peromyscus (Deer Mouse) because they are higher crowned with more prominent 
cusps. Onychomys cf. leucogastor was in the Rancholabrean fauna from Papago Springs 
Cave, Santa Cruz County, Arizona (Skinner 1942). Onychomys species has been found 
in two Late Wisconsin packrat middens from Arizona: Wolcott Peak #5, Pima County, 
dated at 12 130 ± 500 B.P., and Brass Cap Point #1, Yuma County, dated at 1 1 450 ± 
400 B.P. (Mead et al. 1983). Two species of Grasshopper Mice {O. leucogastor and O. 
torridus) are widespread in grassland, desert-grassland and desertscrub habitats in the 
southwestern United States and northern Mexico. Both species live near the fossil site 
today. 



Sigmodon species— Cotton Rat 

Material. -Maxilla with RM'-^ RM' (1 1 144), LM' (1 1 143), dentary with RMi_3. 

Comments.— ThQSQ specimens are from a medium-sized cricetid rodent and are 
referred to the genus Sigmodon because of the distinctive tooth morphology. Sigmodon 
hispidus (Hispid Cotton Rat), S". ochrognathus (Yellow-nosed Cotton Rat), and S. 
minimus (Red-bellied Cotton Rat) are present in southern Arizona and northern Sonora 
today. Sigmodon hispidus is now considered to be three species: S. hispidus, S. mas- 
cotensis, and S. arizonae based on different numbers of chromosomes (Zimmerman 
1970); the form in northern Sonora is S. arizonae. 

Sigmodon species was reported in Arizona from the late Pleistocene Rancholabrean 
Murray Springs Arroyo Fauna, Cochise County (Lindsay and Tessman 1974), from 
the Late Wisconsin/Early Holocene Deadman Cave, Pima County (Mead et al. 1984), 
and in the Early Holocene Wellton Hills #2 packrat midden, Yuma County (Mead, 
et al. 1983). Sigmodon ochrognathus and Sigmodon species were found in Wolcott 
Peak #2 packrat midden, a mixed Middle Holocene and Late Wisconsin sample from 
Pima County, Arizona (Mead et al. 1983). 



49 



Table 1. Vertebrates of the Rancho la Brisca local fauna (Late Pleistocene: Rancholabrean Land Mammal 
Age; Sangamon Interglacial) of Sonora, Mexico, t = Extinct. 



Fish 

Castostomus wigginsi—OpaXa Sucker 
Agosia chrysogaster—Longfin Dace 
Indeterminate cyprinid 
Poeciliopsis occidentalis— Gila Topminnow 
Poeciliopsis monacha-occidentalis—A\\-{emale 
Topminnow 

Amphibians 

Bufo alvarius—ColoaTdo River Toad 
Bufo cf cognatus— Great Plains Toad 
Bufo cf kelloggi—LiXl\e Mexican Toad 
Bufo mazatlanensis —SinaXoa Toad 
Bufo punctatus—Red-spolted Toad 
Bufo species— Toad 
Hyla arenicolor— Canyon Treefrog 
Hyla species— Treefrog 
Pternohyla fodiens— Burrowing Treefrog 
Hylactophryne august i—BarVing Frog 
Leptodactylus melanonotus—Sahinal Frog 
Gastrophtyne cf. olivacea—GvtaX Plains Narrow- 
mouth Toad 
Scaphiopus cowc/zz— Couch's Spadefoot Toad 
Scophiopus species— Spadefoot Toad 
Rana ""pipiens'" Complex — Leopard Frog 



Reptiles 

tcf Terrapene— Box Turtle 
Pseudemys scripta—Yaqui Slider 
Kinosternon flavescens—YeWov/ Mud Turtle 
Kinosternon sonoriense—Sonoran Mud Turtle 
cf Callisaurus draconoldes—Zebra-\ai\ed Lizard 
Sceloporus cf c/arA:// — Clark's Spiny Lizard 
Hypsiglena torquata—NighX Snake 
Masticophis cf. mentovarius— Tropical Whipsnake 
Salvadora species— Patch-nosed Snake 
Thamnophis cf c.vr/op5/5— Black-necked Garter- 
snake 
Crotalus a/rox— Western Diamondback Rattlesnake 

Birds 

Anas cf cr^'cca- Green-winged Teal 

fcf Spizaetos—WavjlL-eaglc 
Indeterminate falconiform— ?Eagle 
Meleagris gallopavo— Common Turkey 

fStrix hrea—La Brea Owl 
Indeterminate Emberizinae— Junco or Sparrow 
Agelaius phoeniceus—Kcd-V<ingQd Blackbird 

Mammals 

Bassariscus species— Ringtail 
fCamelops species— Camel 

Odocoileus hemionus— Mule Deer 
"fCapromeryx c{. minor— La Brea Pronghom 
fTetrameryx species— Four-homed Antelope 
^ Bison species— Bison 
fEquus cf tau— Pygmy Onager 
fEquus species— Horse 
^Mammuthus species— Mammoth 

Dipodomys species— Kangaroo Rat 

Neotoma species— Packrat 

Onychomys species— Grasshopper Mouse 

Sigmodon species— Cotton Rat 



Faunal Analysis 

A total of 493 bones representing 51 taxa of vertebrates from 29 families are 
identified from the Rancho la Brisca local fauna. The fauna includes fishes (5), anurans 
(12), reptiles (11), birds (7), and mammals (13). The fish, amphibians, and reptiles 
represent 60.8% of the species and 92.9% of the identified specimens, while birds were 
13.7% and 1.8%, and mammals were 25.5% and 5.3%, respectively. These percentages 
are unusually low for mammals in late Pleistocene sites, but may be explained by the 
ancient sedimentary environment at la Brisca (see below). 

Percentages of the total number of identified elements were used in the analyses 
because minimum number of individuals (MNI) does not reflect the abundance of some 
groups (e.g., snakes) very well, and it was not possible to compare fossils collected over 
a six-year period and deposited regularly into the collection in Mexico City. Most bones 
appear to represent separate individuals, with a few exceptions (e.g., the 20 vertebrae 
from Masticophis cf. mentovarius). 

The fauna is strongly biased toward medium- and small-sized animals (i.e., less 
than 0.5 kg). The bones o^ Leptodactylus melanonotus, Gastrophryne cf olivacea, and 
all of the fish are very small. There were only ten species of large animals, all except 
the eagle and hawk-eagle being mammals. These bones represent 19.6% of the species, 
but only 3.0% of the identified bones. 



50 

Nine (or ten, if the cf. Terrapene represents an extinct form) of the species (or 
17.6-19.6% of the fauna) are extinct. Twenty bones from extinct animals account for 
4.1% of the total. Warm blooded animals account for most of the extinction: birds, 
28.6% of species and identified bones; mammals, 53.8% of species and 61.7% of iden- 
tified bones. By contrast, 2.6% of the species and 1.0% of the bones of cold blooded 
animals are from extinct animals. None of the fish or amphibians, and perhaps only 
cf Terrapene among the reptiles, were affected by the extinction at the end of the Late 
Wisconsin about 1 1 000 years ago (Martin 1973). 

There is a strong bias in the fauna towards aquatic animals: 10 (19.6%) species 
and 69.9% of the identified bones. Besides fishes these include Hyla arenicolor, Lep- 
todactylus melanonotus, Rana "p/p/^«5 "-complex, Pseudemys scripta, Kinosternon fla- 
vescens, K. sonoriense, Thamnophis cf cyrtopsis, and Anas cf crecca. The remainder 
of the anurans and the Red- winged Blackbird are considered semiaquatic because some 
period of their life history is associated with water. Mud Turtles and Leopard Frogs 
dominate the fauna, with 55.9% of the identified bones. The totals for the aquatic and 
semiaquatic animals combined are 49.0% of the species, and 87.2% of the identified 
bones. The terrestrial animals in the fauna represent 5 1 .0% of the species, but only 
12.8% of the bones. 

Paleoen vironments 

The Rancho la Brisca fauna is dominated by small, aquatic and semiaquatic an- 
imals that are found in permanent stream or cienega habitats. At least locally, the water 
was deep enough to support Pseudemys scripta. Catostomus wigginsi lives in stream 
pools with moderate current. The most abundant species, Rana "'pipiens'" -complex 
and Kinosternon sonoriense, also require fresh water. The association of the fauna and 
the fine-grained clay matrix of the la Brisca sediments suggest that the fossils were 
preserved in a well-developed cienega habitat (Hendrickson and Minckley 1984), sim- 
ilar to the nearby Saracachi Cienega with its stream inlet, open pools, and marsh located 
in the center of a relatively open stream valley (Fig. 2). The riparian gallery forest near 
the inlet pools of the Rancho la Brisca paleocienega provided roosts for raptorial birds 
whose pellets would have been a source for the bones of smaller vertebrates preserved 
in the sediments. The permanent water probably attracted the large mammals and their 
predators. Occasional floods probably account for the minor gravel component in the 
otherwise fine-grained sediments. The la Brisca sediments, perched 15 m above the 
modem streambed, indicate the former base level of the Rio Santo Domingo which 
has incised into the soft indurated stream gravels subsequent to the deposition of the 
la Brisca fauna. 

Zoogeography 

Many fishes of the Magdalena, Sonora, and Yaqui systems are closely related to 
or conspecific with species in the Gila River of Arizona and New Mexico (Miller 1958, 
Minckley 1973, Hendrickson et al. 1980). Catostomus bernardini of the Rio Yaqui is 
allied to C. insignis of the Gila River. The distributions o{ Agosia and Poeciliopsis also 
indicate former connections between the rivers of Sonora and southern Arizona and 
New Mexico. Kinosternon sonoriense is common in most of the rivers of southeastern 
Arizona, northwestern Chihuahua and Sonora, further suggesting stream connections 
in the past. 

By the late Pliocene, Kinosternon flavescens apparently reached the Gila River 
drainage in southeastern Arizona from the central United States. The Blancan fossils 
from the San Pedro River Valley were already differentiated into the Sonoran subspecies 
K. f. arizonense by about three million years ago (Iverson 1979^). This turtle has 
adapted its breeding activities to coincide with the intense summer rainy season rather 
than spring rains. Today it is found from south-central Arizona on the Papago Indian 
Reservation through central Sonora as far south as the Rio Yaqui south of Guaymas 
(Iverson 1919 b, Seidel 1978). The western drainages occupied by K.f. arizonense drain 



51 



southward and are isolated from the Gila-Colorado system (including the San Pedro 
River) to the north. The only permanent aquatic habitats in these areas are artificial 
stock ponds. Kinosternon f. arizonense probably evolved in southeastern Arizona and 
dispersed south into Sonora at a time when the San Pedro River and Sonoran systems 
were connected. The present, isolated populations in Arizona probably dispersed from 
Sonora during a warm, wet interstadial period, rather than directly from southeastern 
Arizona. 

Pseudemys scripta is a large aquatic turtle found from the southeastern United 
States to western Texas, south to Central America, and up the western coast of Mexico 
into central Sonora and southern Baja California. It has a rich fossil record east of the 
Continental Divide, but has not been recorded in Pliocene or Pleistocene deposits in 
Arizona, although it has now been found in Irvingtonian and Rancholabrean deposits 
in Sonora. Apparently, P. scripta never dispersed from Mexico into Arizona, suggesting 
that the connections between river systems were short-lived, shallow streams. Consid- 
ering the fossil record of the cold-blooded groups represented, the past stream con- 
nections probably began in the Late Pliocene providing multiple opportunities for 
dispersals of some animals. 

Paleoclimates and Age of Fauna 

Five animals in the fauna {Bufo cf kelloggi, B. mazatlanensis, Leptodactylus mel- 
anonotus, Pternohyla fodiens and Masticophis cf. mentovarius) no longer live in the la 
Brisca area, but are present to the southwest and southeast in Sonoran desertscrub and 
Sinaloan thomscrub communities. Bufo alvarius, cf. Callisaurus draconoides, and Sce- 
loporus cf clarkii are other Sonoran elements in the fauna that live in desertscrub, 
thomscrub, or oak woodland/desert-grassland communities which are found in the 
Rancho la Brisca area today. Hylactophryne augusti is another animal that just reaches 
Arizona, but is widespread in central and eastern Mexico. The area where most of the 
species in the la Brisca fauna occur together today would be along the Rio Yaqui near 
El Novillo east of Hermosillo (Figs. 1 and 14), about 240 km SSE of la Brisca. 

The biota of the Sonoran Desert becomes more subtropical to the south and east 
as the number of freezes per winter decreases, and the total annual precipitation and 
the percentage of summer rainfall increase (Hastings and Turner 1965). The presence 
of subtropical Sonoran animals suggests that the la Brisca fauna lived in a climate with 
fewer winter freezes and substantially greater summer rainfall than occurs in the area 
today. 

Fossil packrat middens provide detailed chronologies of vegetation and climate 
for the last 30 000 years for many desert areas in the southwestern United States (Van 
Devender and Spaulding 1979). The general Middle and Late Wisconsin (35 000-1 1 000 
B.P.) paleoclimatic reconstruction from the midden record for the area between 32- 
36°N latitude includes mild winters with greatly increased rainfall and cool summers 
with greatly decreased rainfall. There was little summer rainfall in the present Sonoran 
Desert in western Arizona. A Middle Wisconsin packrat midden from west of Her- 
mosillo, Sonora, recorded the expansion of some woodland trees into low areas in 
central Sonora during the last glacial period (Wells and Hunziker 1976). The la Brisca 
fauna, however, is more likely to reflect a thermal maximum during an interglacial 
with increased summer monsoons and an expansion of subtropical communities into 
north-central Sonora. The climate of the Late Holocene (4000 B.P.-present) was prob- 
ably similar to the paleoclimate of the la Brisca fauna. 

The Rancholabrean Land Mammal Age began at the end of the Yarmouthian 
Interglacial and the beginning of the Illinoian Glacial. Previously, an interstadial Ran- 
cholabrean fauna like that of la Brisca would have been placed in the Sangamon 
interglacial period between 125 000 and 70 000 years ago. At least ten Rancholabrean 
faunas in Florida have been assigned to the Sangamon interglacial, although few faunas 
in the western United States have been correlated with that period (Kurten and An- 
derson 1980). However, the beginning of the Rancholabrean was recently correlated 
with the Brunhes normal magnetic polarity zone at about 690 000 B.P. (Kurten and 



52 




Figure 14. Three miles above Soyopa on Rio Yaqui between El Novillo and Tonichi in July 1983. Lep- 
todactylus melanonotus (Sabinal Frog) live in moist side of river, Pseudemys scripta (Yaqui Slider) sun on 
exposed bank on far side of river. Masticophis mentovarius striolatus (Tropical Whipsnake) was observed 
on the slopes. Slope vegetation is mostly tropical deciduous forest with Sinaloan thomscrub on drier aspects 
and inland away from river. This area is 240 km SSE of la Brisca. 



Anderson 1980, Lindsay et al. 1975). With the inferred length of the Illinoian Glacial, 
the correlation of the Rancholabrean with glacial/interglacial sequences is no longer 
clear. Sangamon faunas could actually correlate with any of the five or so earlier warm 
periods recorded in oxygen isotope sequences from deep-sea cores (Imbrie and Imbrie 
1979). However, the arrival of Bison south of the continental ice sheets now appears 
to have been between 1 70 000 and 1 50 000 years ago (C. A. Repenning, personal 
communication 1984). The presence of Bison species places the fauna in the last in- 
terglacial, the traditional Sangamon. 



Acknowledgments 

Richard S. White and Dr. Arturo Oliveras, Centro Regional Noroeste, Hermosillo, 
discovered the site and encouraged this study. Ismael Ferrusquia V. and Oscar Carranza 
C, Instituto de Geologia, Ciudad de Mexico, arranged for a collection permit and have 
accepted the fossils for the Mexican government. John B. Iverson, Earlham College, 
identified the Kinosternon material. Jim Honey, University of Arizona, identified the 
Camelops species navicular. David W. Steadman, Smithsonian Institution, identified 
the turkey. Rob McKenzie and George T. Jefferson, Los Angeles County Museum of 
Natural History, examined the antilocaprids and the eagle. Christopher A. Shaw, George 
C. Page Museum, provided information about the El Golfo, Sonora, fauna. Kevin B. 
Moodie, Louis H. Taylor, Louis L. Jacobs, and Everett H. Lindsay, University of 
Arizona Laboratory of Paleontology, curated and made casts of the la Brisca fossils. 
Kenneth L. Petersen, Robert S. Thompson, and Vera Markgraf, University of Arizona, 
processed the pollen samples. Charles H. Lowe, Jr., John K. Cross and Cecil Schwalbe 
provided unpublished locality records for Sonoran amphibians and reptiles in the 
University of Arizona herpetological collection. Howard Lawler, Arizona-Sonora Des- 
ert Museum, provided common names and observations for Sonoran amphibians and 



53 



reptiles. Jim I. Mead, Kevin B. Moodie, Stephen F. Hale, Owen K. Davis, and Paul 
S. Martin (University of Arizona), Ellie Baker Koon (University of Michigan), Edie 
Marsh (University of Texas), and R. Wayne Van Devender (Appalachian State Uni- 
versity) helped in the field work. Paul S. Martin, Larry Marshall, Jim Mead, Kevin 
Moodie and Bob McCord (University of Arizona), Gregory K. Pregill (San Diego 
Natural History Museum), and Robert R. Miller (University of Michigan) commented 
on the manuscript. We especially thank the Don Crescentio Palafox family of Rancho 
la Brisca for their hospitality. 

Financial support was provided by National Science Foundation grants DEB #76- 
19784 and DEB #80-22773 to Thomas R. Van Devender and DEB #75-13944 to Paul 
S. Martin, Department of Geosciences, University of Arizona. Drafts of this manuscript 
were prepared by Margaret Madouse, Deborah Gaines, Betty Fink and Jean Morgan. 
Julio Betancourt translated the abstract into Spanish. 

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1,^^ TRANSACTIONS 

^ OF THE SAN DIEGO 

SOCIETY OF 
NATURAL HISTORY 



Volume 21 Number 3 pp. 57-70 29 October 1985 

L/eRARy 

Floral morphology, nectar production, and breeding systems in 
Dudleya subgenus Dudleya (Crassulaceae) 

Geoffrey A. Levin L* - - 

Department of Botany, San Diego Hatuml Historv Kf^eum, San Diego, California 92112 USA 

Thomas W. Mulroy 

URS Company, HI W. Micheltorena, 3rd Floor, Santa Barbara, California 93101 USA 

Abstract. Floral morphology, nectar production, and breeding systems of 2 1 taxa in Dudleya 
subgenus Dudleya suggest three reproductive strategies. Most species— 13 of those examined — have 1- 
1 5% auto-fertility (defined as the proportion of seed set by self-pollination in the absence of pollinators) 
and produce nectar with about 2-5 mg sugar per flower. These species, which are predominantly coastal 
in distribution, have dense inflorescences of yellow flowers and appear to be pollinated primarily by 
bees and long-tongued flies. Increased seed set and seedling vigor with cross-pollination select for 
outcrossing in these species. A second group of three species has long-tubed, frequently pendent, red 
flowers in very open cymes, high auto-fertility (about 40-60%), and abundant nectar— yielding 5-12 
mg sugar/flower. Ranging from hills near the coast to desert mountains, these species are hummingbird- 
pollinated. The remaining three species (one with three subspecies) have short-tubed flowers in dense 
cymes, high auto-fertility (25-50%), and nectar production of less than 2.5 mg sugar/flower. These 
species are typically montane and occupy habitats with shorter and less reliable growing seasons than 
are usual for the genus. Environmental unpredictability and pollinator unreliability may explain the 
apparent trend toward autogamy in the third group and the high auto-fertility of the hummingbird- 
pollinated species. Because flowers are protandrous, even species with high auto-fertility maintain the 
ability to outcross if pollinators are available. 

Introduction 

The genus Dudleya (Crassulaceae) consists of about 40 species of succulent rosette 
perennials of western North America (Moran 1951, 1959). Subgenus Dudleya is the 
most diverse (about 25 species) and most widespread of the three subgenera. The 
greatest diversity is in coastal and insular southern California and Baja California, 
although the subgenus extends from the Cape Region of Baja California to coastal 
southern Oregon and inland to southern Nevada and central Arizona, spanning an 
altitudinal range from sea level to 2750 m. Habitats include coastal bluffs, montane 
canyons, and slopes of desert mountains. About half the species are narrow endemics, 
many of them insular; the remainder are widespread. Except in a few species of coastal 
northern Baja California, distributions are mostly patchy, with populations commonly 
small and well isolated. 

Given the great diversity of habitat and population structure of its species, Dudleya 
might be expected to vary in 1) breeding systems, 2) pollination syndromes, and 3) 
reproductive strategies. Some aspects of pollination biology have been shown to vary 
within groups of related plants, e.g., at the family level in Polemoniaceae (Grant and 
Grant 1965) and Bignoniaceae (Gentry 1 974), and at the generic level in Agave (Schaffer 
and Schaffer 1977), Leavenworthia (Lloyd 1965, Solbrig 1976, Solbrig and Rollins 
1977), Pedicularis (Sprague 1962, Macior 1968, 1970), Rhododendron (Stevens 1976) 
and Trichostema (Spira 1980). Yet, except in Spira's study, variation in all three aspects 
has not been examined in a single genus. 



58 



Methods 



We studied floral morphology, nectar production, and breeding systems in field- 
collected plants grown in a glass-topped screenhouse at Rancho Santa Ana Botanic 
Garden, Claremont, California. Localities of the populations studied are listed in the 
Appendix. As noted below, we also made some field measurements of nectar production. 
We also observed pollinators on several species, although most observation periods 
were relatively short. 

We determined nectar volume by extracting all nectar from a flower with a vol- 
umetric (5-Ail or 10-/ul) capillary tube. Upon sampling, we immediately measured the 
concentration (in mg sucrose equivalent/mg solute) of sugar in the extracted nectar with 
a hand-held Bausch & Lomb sucrose refractometer. We converted concentrations to 
mg sucrose equivalent/ml solution using Table 88 in the 59th edition of the Handbook 
of Chemistry and Physics (1978-1979:D-308) and then calculated total sugar by mul- 
tiplying concentration by nectar volume (Bolten et al. 1979). 

To determine phenology of nectar production and variation in nectar concentration 
and volume with flower age, we sampled flowers at different stages of anthesis. The 
first season, we recorded the relative age of each flower. The second season, in order 
to obtain measurements on the basis of absolute time, we sampled flowers at daily 
intervals after they opened. Because sampling often damaged the flower, we could not 
reliably resample the same flower. Instead, for each time period, we sampled 1 flowers, 
chosen from several plants. 

On each flower sampled for nectar, we measured the length of the corolla tube, 
that portion of the corolla in which adjacent petals are fused; sample sizes ranged from 
50-80 flowers. We also recorded flower color and positions of anthers and stigmas. 

To determine the breeding systems of the different species, we mechanically self- 
pollinated some flowers, mechanically cross-pollinated others, emasculated others in 
bud, and left others untouched. We allowed fruits to mature on the plants but removed 
them before dehiscence. Percentage seed set was determined by dividing the number 
of developed seeds by the total number of ovules. Unfertilized ovules were small and 
withered, making them easy to distinguish from the larger plump seeds. Typically, three 
flowers from three diflerent plants were included in each treatment. 

For six species, we compared viability and seedling vigor of seeds from self- 
pollinated and cross-pollinated flowers by planting 30 seeds from each treatment and 
counting the number of seedlings at three and seven weeks after sowing. 

Pollinators 

Floral morphology suggests that there are two different groups of pollinators. In 
aU species of subgenus Dudleya, the petals are essentially erect, with the overlapping 
edges usually closely appressed above the corolla tube (Fig. 1). In the relatively small 
flowers of most species (7-15 mm long), nectar is available to small bees and flies that 
can crawl into the corollas, and to larger insects with moderately long tongues. These 
species primarily have yellow to orange flowers, many with ultraviolet reflectance 
patterns (T. W. Mulroy, pers. obs.), borne erect in more or less flat-topped inflorescences 
that would serve well as insect landing platforms (Figs. 1 and 2A). Apparently the genus 
has little ability to produce a floral scent: only three species, none of them in subgenus 
Dudleya, produce any aroma (Moran 1951, 1959; pers. obs.)} We have observed bees 
of eight genera and occasional butterflies visiting Dudleya flowers (G. A. Levin in prep.); 
Moldenke (1976) listed bees in the genera Bombus and Anthophora as important pol- 
linators of Dudleya. 

Three closely related species, D. arizonica, D. anthonyi, and D. pulverulenta (Fig. 
2B, C), appear to be hummingbird pollinated. The latter two, in particular, possess a 



' Although Johansen (1935) reported that flowers of Z). echeverioides. now regarded as a synonym of D. 
greenei, have an odor resembling woodland violets, neither we nor Moran (1951) has been able to detect 
any floral fragrance in D. greenei. 



59 




Figure 1. Inflorescence of Dudleya greenei. Arrows labeled A indicate young flowers (1-2 days old); the 
anthers have dehisced and are positioned toward the center of the corolla. Arrows labeled B indicate older 
flowers (3-5 days old); the styles have elongated, positioning the now receptive stigmas near the mouth of 
the corolla, and the anthers are positioned near the edge of the corolla. As the flowers age further, the anthers 
will again move toward the center. (Photo by Reid Moran.) 



suite of characteristics associated with hummingbird pollination (Faegri and van der 
Pijl 1979, Grant and Grant 1968). Their corollas are 1.5-2 cm long, fused about 1 cm, 
and colored deep red. The flowers are pendent on long, slender pedicels, becoming 
erect in fruit. The inflorescences of these species are typically more open than in the 
remainder of the species. Dudleya arizonica also has red flowers, but they are somewhat 
smaller (1.2-1.4 cm long) and erect in more dense inflorescences. By probing flowers 
with a dead hummingbird (sp. indet.), we found that hummingbirds could effect pol- 
lination while feeding, and we have observed them foraging on D. piilverulenta and D. 
arizonica. We also observed hummingbirds visiting D. hhttonii, D. cymosa cymosa, 
and D. ingens, species that are better adapted for bee pollination (G. A. Levin in prep.). 
Grant and Grant (1966) reported hummingbirds visiting D. cymosa minor and D. 
lanceolata, and Moldenke (1976) considered hummingbirds to be the principal polli- 
nators of Dudleya, although he did not indicate which species he observed. 



Nectar Production 

Phenology^ —In Dudleya, the nectaries are located at the base of the gynoecium. 
The flowers are strongly protandrous (Fig. 1), and nectar volume and concentration 
are correlated with the age of the flower (Fig. 3). No nectar is produced before the 
anthers release pollen. Following anther dehiscence, nectar is secreted rapidly and 



60 




Figure 2. A— Flowering plant oi Dudleya greenei, typical of bee-pollinated Dudleya species (photo by Reid 
Moran). B, C— Flowering plant and inflorescence, respectively, of Dudleya pulverulenta, typical of hum- 
mingbird-pollinated Dudleya species. 



61 



o) 2 

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o 

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QC 1 
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- 


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1 1 


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NECTAR CONCENTRATION 




5 


- 


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NECTAR VOLUME 


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50 



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30 O 



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- 20 



- 10 



1 2 3 4 5 6 7 

DAYS AFTER OPENING 

Figure 3. Phenology of nectar production in Dudleya nuhigena. representative of the typical pattern in 
subgenus Dudleya. Points indicate mean values. Concentration is in g sugar/ 1 00 g solution. Flowers are 
protandrous; stigmas become receptive on day 2. 



62 



Table 1 . Characteristics of nectar production and corolla tube length in Dudleya subgenus Dudleya. "Max- 
imum" denotes the mean of the three highest measurements of that characteristic. Concentration is in g 
sucrose equivalent/ 100 g solution. Energy content is based on 4 cal/mg sugar (Heinrich 1975). 











Maximum 


Maximum 






Maximum 


Minimum 


Cone, at 


sucrose 


energy 


Corolla 




volume 


cone. 


max. vol. 


content 


content 


tube length 


Dudleya species 


Ml 


% 


% 


mg 


cal 


mm 


abramsii 


trace 


— 


— 


— 


— 


1.4 


acuminata 


4.8 


36 


51 


3.4 


13.6 


4.2 


albiflora 


4.2 


37 


42 


2.1 


8.4 


4.3 


(2 populations) 


5.6 


— 


46 


4.1 


16.4 


5.0 


anthonyi 


14.0 


34 


40 


9.5 


38.0 


6.0 


arizonica 


9.2 


— 


31 


4.8 


19.2 


5.7 


(3 populations) 


5.6 


29 


40 


2.9 


11.6 


6.2 




16.0 


25 


35 


7.8 


31.2 


7.0 


bettinae 


1.8 


36 


48 


1.1 


4.4 


1.0 


brittonii 














glaucous form 


3.4 


40 


51 


2.3 


9.2 


2.9 


(2 populations) 


7.4 


— 


50 


4.7 


18.8 


3.2 


green x glaucous 


6.8 


— 


26 


4.1 


16.4 


3.8 


caespitosa 


11.5 


— 


51 


7.2 


28.8 


2.4 


(2 populations) 


11.5 


— 


34 


4.6 


18.4 


2.4 


cultrata 


3.1 


32 


37 


1.6 


6.4 


1.9 


(2 populations) 


8.9 


— 


30 


4.8 


19.2 


3.7 


cymosa cymosa 


2.8 


35 


38 


1.1 


4.4 


1.1 


c. marcescens 


3.7 


26 


40 


2.0 


8.0 


1.1 


c. ovatifolia 


4.8 


22 


32 


2.4 


9.6 


1.6 


gatesii 


13.5 


32 


44 


6.8 


27.2 


6.1 


greenei 


4.7 


51 


58 


3.5 


14.0 


1.3 


ingens 














coastal form 


4.0 


29 


51 


2.3 


9.2 


2.0 


(2 populations) 


12.0 


— 


33 


5.9 


23.6 


5.0 


inland form 


7.3 


— 


49 


4.8 


19.2 


5.0 


lanceolata 


9.0 


25 


42 


4.4 


17.6 


2.3 


linearis 


2.3 


27 


44 


1.3 


5.2 


2.0 


nubigena 


5.0 


24 


28 


2.2 


8.8 


3.2 


parva 


trace 


— 


— 


— 


— 


1.9 


pulverulenta 


44.0 


23 


25 


14.3 


57.2 


7.7 


(2 populations) 


32.1 


20 


30 


12.5 


50.0 


8.0 


saxosa saxosa 


5.7 


32 


38 


2.5 


10.0 


1.8 



collects in the base of the corolla tube. Volume and concentration increase throughout 
the male phase of anthesis, reaching maximum volume soon after the stigmas become 
receptive. Thereafter, nectar volume tends to decrease and concentration continues to 
increase, probably because of a cessation or attenuation of nectar secretion and evap- 
oration of water from the nectar. 

Sugar content, like nectar volume, increases rapidly through the male phase and 
reaches a maximum after the stigmas become receptive (Fig. 3). Thereafter sugar content 
remains essentially constant, again suggesting that nectar secretion had ceased. Other 
genera have similar patterns of age-related nectar production (Anderson 1976, Car- 
penter 1976, Feinsinger 1978, Pyke 1978, Cruden et al. 1983). 

The phenology of nectar production in Dudleya is highly economical. During the 
male phase of anthesis, visiting foragers pick up pollen on their bodies and may carry 
it to other flowers. Pollinators continue to be attracted to a flower until stigmas are 
receptive, but soon thereafter no more nectar is produced to reward their visits. The 
flower will probably have been pollinated by this time, so further visits are unnecessary. 
Within 24 h following pollination (provided the stigmas are receptive), the flower closes. 
However, unpollinated flowers remain open for up to five days after the stigmas become 
receptive, and because no morphological changes are associated with the cessation of 
nectar production, it is likely that pollinators will continue to be attracted to unpolli- 
nated flowers by previously accumulated nectar. 



63 



44 



32 



_ 16 



CC 

< 

o 

LU 



14 



12 



X 

< 



8 




r = 0.71 
p< 0.001 



LENGTH OF COROLLA TUBE, mm 

Figure 4. Relationship between maximum nectar volume and corolla tube length in Dudleya subgenus 
Dudleya. Each point represents one population. Linear correlation of r = .71 is significant (f < .001). 



Environmental factors affect nectar production in Dudleya. Cool, cloudy weather 
reduces the rate of secretion: in some cases only a trace of nectar accumulated in flowers 
open for three rainy days. Similar meteorological effects on nectar production have 
been observed in alfalfa (Pederson 1953, Walker et al. 1974) and Ipomopsis (Pleasants 



64 





60 


















• 






55 


— 






















50 


- 
















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- 




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35 


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h- 




















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3 


20 


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10 


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• 


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1 




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1 < 





1 2345678 

LENGTH OF COROLLA TUBE, mm 

Figure 5. Relationship between maximum energy content of nectar and corolla tube length in Dudleya 
subgenus Dudleya. Each point represents one population. Linear correlation of /■ = .77 is significant (P < 
.001). 



1983) and have been attributed to low temperature and low sunlight. Understandably, 
the volume of accumulated nectar remains higher and the concentration lower when 
the weather is cool and humid than when it is warm and dry. The loose fit of the points 
to the curves in Figure 3 probably results in part from changes in light, temperature, 
and humidity during our study. 

Quantity. —Nectar volume, maximum sugar content, and maximum caloric con- 
tent vary considerably among species and even among populations in some species. 
Nectar concentration varies to a lesser extent (Table 1). Field measurements with D. 
cymosa cymosa and D. brittonii agree with our greenhouse results. 

We find strong positive correlations between maximum nectar volume and corolla 
tube length (r = .71; Fig. 4) and between maximum caloric content and corolla tube 
length (r = .77; Fig. 5). These results suggest that the degree of petal fusion, an important 
taxonomic character in this genus, has a functional significance. Larger flowers with 
longer corolla tubes might be expected to require larger pollinators, which require more 
energy and thus more nectar (Heinrich and Raven 1972) than smaller flowers could 
hold. 

The quantities of sugar offered by the flowers support the hypothesis that most 



65 

Table 2. Number of living seedlings from self-pollinated flowers and cross-pollinated flowers of Dudleya. 
Thirty seeds from each treatment were sown. 









Time 


after 


sowing 










3 weeks 




- 




7 weeks 




Dudleya species 


Selfed 




Crossed 


Selfed 




Crossed 


brittonii 
cult rat a 


14 
29 




23 
26 




8 
4 




14 

22 


cymosa marcescens 
c. ovatifolia 
ingens 

2 plants 
linearis 


4 
6 
9 
4 

15 




4 
2 
3 
5 
9 




2 
7 
8 
3 

7 




3 

6 

10 

5 

11 



Species of Dudleya are pollinated by bees and flies, but that some have evolved for 
pollination by hummingbirds. Nectar accumulates over about three days, with a daily 
energy production of 2-3 cal/flower/day for most species. These values are similar to 
some temperate bee-pollinated flowers (Heinrich 1975, 1976, Reader 1977, Rust 1977, 
Schaffer and Schaffer 1977). Unless insects were excluded from the flowers, the nectar 
energy would be too small for temperate hummingbirds, which require an intake of 
5.5-7.5 kcal/day (Pearson 1954, Stiles 1971), or about 1.5-2.0 g sugar/day (Heinrich 
1975). In species that produce large quantities of nectar (up to 7-8 cal/flower/day), the 
longer corolla tubes, red corolla color, and pendent flower position probably all help 
prevent feeding by most bees and flies. Although 1000-1 500 flowers would be required 
to support one hummingbird for a day, this number is not inconsistent with some 
observations (Pearson 1954). Clearly nectar quantities are small enough not to satiate 
pollinators, and thus small enough to encourage outcrossing, even if several flowers 
are open simultaneously on each plant (Heinrich and Raven 1972). Nectar concentra- 
tions are all within the range typical of both bee- and hummingbird-pollinated species 
(Hainsworth 1973, Heinrich 1975). 

Breeding Systems 

Phenology of ant hesis.— As noted above, Dudleya flowers are protandrous (Fig. 
1). Anthers and stigmas are initially separated by a few millimeters. About two days 
after the anthers dehisce, the styles elongate and the stigmas become receptive. As a 
flower ages, the filaments of its stamens shrivel and the anthers may then contact the 
stigmas, transferring any remaining pollen. Contact typically occurs four to six days 
after the flower opens. 

Seed set. —All species examined are self-compatible and capable of some auto- 
fertilization (self-pollination in the absence of pollinators) (Fig. 6). Compared to the 
other species we investigated, D. cymosa, D. nubigena, D. pulverulenta and one pop- 
ulation of i). brittonii had high auto-fertility. D. cymosa in particular departs from the 
general morphological pattern in that its stamens form a tight ring around the stigmas 
deep within the corolla tube, thereby facilitating transfer of pollen as the flowers age. 

Except in highly auto-fertile subspecies of D. cymosa and in D. pulverulenta, me- 
chanical self-pollination produced significantly higher seed set than did auto-fertiliza- 
tion, in most cases by a factor of two or more. Cross-pollinated flowers usually produced 
nearly twice as many seeds as self-pollinated flowers. Thus, for most species, there is 
clearly an advantage to attracting pollinators. The increased seed set of outcrossed 
flowers may be the result of fewer homozygous combinations of deleterious genes (D. 
A. Levin 1971), or faster pollen tube growth of cross-pollen, resulting in more successful 
fertilization (Bateman 1956, Smith and Clarkson 1956, Weller and Ornduff" 1977). 

Seed viability and seedling vigor. —Table 2 shows the number of seedlings present 
three and seven weeks after sowing 30 seeds each from self- and cross-pollinated flowers 
of six taxa. There is no significant diflerence between the number of seedlings from 



66 



DUDLEYA SPECIES: 

CYMOSA CYMOSA 

CYMOSA MARCESCENS 

GREENEI 

ABRAMSM 

CYMOSA OVATIFOLIA 

SAXOSA SAXOSA 

LINEARIS 

LANCEOLATA 

CAESPITOSA 

NUBIGENA 

BRITTONII 

CULTRATA 

ACUMINATA 

ALBIFLORA 

INGENS (INLAND FORM) 

GATESII 

ARIZONICA 

PULVERULENTA 



AVERAGE PERCENT SEED SET BY: 



UNTREATED 
(AUTO-FERTILIZATION) 



MECHANICAL 
SELF-POLLINATION 



MECHANICAL 
CROSS-POLLINATION 



to 
O 



O 



a> 
o 



O 



O 



O) 

o 



O 




no data 



o 

— r- 



o 



CD 

o 



no data 



no data 



no data 



Figure 6. Seed set under different treatments in Dudleya subgenus Dudleya. Species are arranged in order 
of increasing corolla tube length. Values are means, typically of three flowers each from three different plants. 



self-pollinated flowers and cross-pollinated flowers three weeks after sowing (Wilcoxen 
paired-sample test; P > .20). Thus, there appears to be no difference in seed viability. 
After seven weeks, however, significantly more seedlings survived from cross-pollinated 
flowers than from self-pollinated flowers (P < .05). In contrast, D. cymosa showed 
approximately equal survivorship from the two treatments, suggesting that, like ha- 
bitually self-pollinating plants, it suffers less inbreeding depression than habitually cross- 
pollinating species (Grant 1975). 

Reproductive Strategies 

When maximum energy content is plotted against auto-fertility, the species fall 
into three groups (Fig. 7). First, there is a large group with relatively low auto-fertility 
(<20%) and moderate to high nectar production. This group contains D. acuminata, 
D. albijlora, D. brittonii, D. caespitosa, D. cultrata, D. gatesii, D. greenei, D. ingens, 
D. lanceolata, and D. saxosa; D. bettinae, a species whose breeding systems we did not 
examine, probably also belongs to this group, as do D. abramsii and D. parva, species 
in which we had difficulty measuring nectar production. The second group comprises 
species with relatively high auto-fertility (25-50%) and little nectar (three subspecies 
of Z). cymosa, D. linearis, and D. nubigena), a combination of characters suggesting at 
least incipient autogamy (Faegri and van der Pijl 1979, Omduff" 1969). Differences 
between the two groups in both nectar production and auto-fertility are significant 
(Mann-Whitney test; P < .001). The third group consists of the putatively humming- 
bird-pollinated species {D. arizonica, D. pulverulenta, and probably D. anthonyi, al- 
though we did not determine its breeding system). 

Our data demonstrate that it is advantageous for most Dudleya species to attract 



67 



50 



40 



yj 

DC 

O 

_i 
< 

o 



lU 



30 



II 



o 
o 


20 


• 


> 




« 


o 




# 


DC 






LU 




Y 


z 




• 


LU 




• 


2 






^ 






^ 


10 


* 


X 






< 







10 



20 



30 



40 



50 



SEED SET BY AUTO-FERTILIZATION 



Figure 7. Relationship between maximum energy content of nectar and auto-fertility in Dudleya subgenus 
Dudleya. Each point represents one population. Species with high auto-fertility produce little nectar (Group 
I), whereas species with low auto-fertility produce moderate amounts of nectar (Group II). The three pop- 
ulations that do not fit this pattern are hummingbird pollinated (Group III). 



pollinators: plants that do so set more seed, whether by self- or cross-pollination. 
Moreover, there are the immediate advantages to outcrossing of increased seed set and 
increased seedling vigor, in addition to probable long-term advantages of increased 
genetic variability (Williams 1975, Solbrig 1976, Gottlieb 1977, Hancock 1977, Solbrig 
and Rollins 1977). 

What then might account for the apparent autogamous tendencies of D. cymosa 
and other members of the group showing high auto-fertility and low nectar production? 
Unlike the majority of Dudleya species, those with this quasi-autogamous syndrome 
are comparatively short-lived perennial plants growing in habitats with short growing 
seasons and with great seasonal variation in environmental conditions. D. cymosa, for 
example, is widespread in the Sierra Nevada, Coast Ranges, and Transverse Ranges 
of California. Conditions that favor autogamy, such as a short and unpredictable re- 
productive season, small population size, high population turnover, and pollinator 
unreliability (Grant and Grant 1965, Vasek 1971, Hinton 1976, Hurka et al. 1976, 



68 



Solbrig 1976, Solbrig and Rollins 1977) could be expected to be more prevalent in 
these environments than in the coastal environment typical of most Dudleya species. 
Although we have not tested the relative importance of these factors, unreliable pol- 
lination does appear to be involved (G. A. Levin in prep.)- 

The high auto-fertility of those species pollinated by hummingbirds is, on face 
value, unexpected. However, preliminary evidence suggests that hummingbirds are 
unreliable pollinators of Dudleya, varying considerably in abundance both temporally 
and spatially (G. A. Levin in prep.). Increased specialization for hummingbird polli- 
nation may concomitantly select for increased ability to set seed in the absence of 
pollinators. 

Even the species with the strongest propensity toward autogamy are protandrous 
and produce sufficient nectar to attract pollinators. The actual amount of auto-fertil- 
ization that occurs in nature depends on the quantity of pollen removed from the 
anthers before they contact the stigmas, in addition to the auto-fertility of the species 
(Arroyo 1975). In Lupinus nanus, a species with synchronous maturation of anthers 
and stigma, plants having more than 30% auto-fertility are predominately autogamous 
(Harding et al. 1 974). Field observations indicate that, because of protandry, only about 
50% of seed set in D. cymosa cymosa results from auto-fertilization in spite of high 
auto-fertility (G. A. Levin in prep.). Dudleya thus has a breeding system that promotes 
outcrossing while maintaining the possibility of auto-fertilization, the balance being 
selected according to the particular environment of the species. 

In conclusion, this study demonstrates the interdependence of breeding system, 
pollination syndrome, and reproductive strategy. A short and uncertain growing season 
and/or pollinator unreliability may make it important to shift the reproductive strategy 
toward assurance of high seed set. In response, the breeding system is shifted toward 
greater auto-fertilization, which in turn requires a change in floral morphology and 
allows lower nectar production— a shift in the pollination syndrome. Thus natural 
selection does not modify one characteristic of the reproductive system without mod- 
ifying various other characteristics. 

Acknowledgments 

We wish to thank G. K. Pregill, R. V. Moran, M. O'Brien, E. A. PhiUips, R. W. 
Thorp, G. L. Webster, and an anonymous reviewer for their constructive criticism of 
earlier drafts, and F. L. Carpenter for her valuable suggestions. We appreciate R. 
Moran's permission to use his photographs for Figures 1 and 2A. Greenhouse space 
was generously provided by Rancho Santa Ana Botanical Garden, Claremont, Cali- 
fornia. Financial support from the Educational Foundation of America and the Egbert 
Schenk Botanical Fund, Pomona College, Claremont, is gratefully acknowledged. 



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69 



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70 

Appendix 

Localities of Dudleya populations studied 

Populations are listed taxonomically in same order as Table 1 . 

D. abramsii Rose. California, San Diego Co.: Highway 94 5.4 km W of Campo. D. acuminata Rose. 
Mexico, Baja California (Norte): Millers Landing. D. albiflora Rose. Mexico, Baja California (Norte): Cedros 
Island; Highway 1 near Rosarito. D. anthonyi Rose. Mexico, Baja California (Norte): Cabo San Quintin. D. 
arizonica Rose. Mexico, Baja California (Norte): Rio Santo Tomas ca. 16 km E of coast; California, San 
Diego Co.: Campbell Grade, Highway 52 ca. 22 km S of Highway 78; Highway 94 4.8 km W of Campo. D. 
bettinae Hoover. California, San Luis Obispo Co.: Cuyucos. D. brittonii Johansen. Glaucous form. Mexico, 
Baja California (Norte): near La Mision; Playa de Punta Banda. Green x glaucous form. Mexico, Baja 
California (Norte): Playa de Punta Banda. D. caespitosa (Haworth) Britton & Rose. California, Los Angeles 
Co.: Topanga Canyon ca. 5 km N of Pacific Ocean; Ventura Co.: Pt. Mugu. D. cultrata Rose. Mexico, Baja 
California (Norte): San Martin Island; Cabo San Quintin. D. cymosa (Lemaire) Britton & Rose ssp. cymosa. 
California, Tulare Co.: Hospital Rock, Sequoia National Park. D. cymosa ssp. marcescens Moran. California, 
Ventura Co.: Little Sycamore Canyon, Santa Monica Mts. D. cymosa ssp. ovatifolia (Britton) Moran. Cali- 
fornia, Los Angeles Co.: Topanga Canyon. D. gatesii Johansen. Mexico, Baja California (Norte): Millers 
Landing. D. greenei Rose. California, Santa Barbara Co.: Prisoners' Harbor, Santa Cruz Island. D. ingens 
Rose. Coastal form. Mexico, Baja California (Norte): San Juan de las Pulgas; Punta Cabras. Inland form. 
Mexico, Baja California (Norte): specific locality unknown. D. lanceolata (Nutt.) Britton & Rose. California, 
Orange Co.: Modjeska Canyon. D. linearis (Greene) Britton & Rose. Mexico, Baja California (Norte): West 
San Benito Island. D. nubigena (Brand.) Britton & Rose. Mexico, Baja California Sur: Cabo San Lucas. D. 
parva Rose & Davidson. California, Ventura Co.: Arroyo Santa Rosa. D. pulverulenta (Nutt.) Britton & Rose. 
Mexico, Baja California (Norte): Rancho Arenoso, ca. 50 km E of El Rosario on Highway 1 ; California, 
Orange Co.: Laguna Beach. D. saxosa (M. E. Jones) Britton & Rose ssp. saxosa. California, Inyo Co.: 
Aguerberry Point, Panamint Mts. 




TRANSACTIONS 
MCZ OF THE SAN DIEGO 

LIBRA^RY SOCIETY OF 

NATURAL HISTORY 



W/IR 26 



1986 



Volume 21 Number 4 pp. 71-79 24 February 1986 



Fishes living in deepsea thermal vents in the tropical eastern 
Pacific, with descriptions of a new genus and two 
new species of eelpouts (Zoarcidae) 

Richard H. Rosenblatt 

Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093 USA 

Daniel M. Cohen 

Natural History Museum of Los Angeles County, Exposition Park, Los Angeles, CA 90007 USA 

Abstract. A new genus and two new species of zoarcid fishes are described from deep sea hydro- 
thermal vent systems in the eastern Pacific. The new genus Thermarces is distinguished from other 
zoarcids by reduction of suborbital bones to one or two, unossified pectoral radials, and lack of fourth 
infrapharyngobranchial bone, postcleithrum, scales and pelvic fins. One species of the genus has been 
taken at 21''N, 109°W, and near the Galapagos Islands, the other at 12°48'N, 104°W. The new species 
are diagnosed and described. The otoliths examined show clear growth rings. 

The objectives of this paper are to distinguish so far as possible the various fishes 
known to hve in warm water vented from deepsea springs in the tropical eastern Pacific. 
Two species of eelpouts appear to be heretofore unknown, and we describe them here. 

One so-called vent fish that has been observed and photographed from the sub- 
mersible ALVIN in and near vents along the Galapagos Rift was referred by Cohen 
and Haedrich (1983) to the genus Diplacanthopoma of the ophidiiform family Bythi- 
tidae (Cohen and Nielsen 1978). Photographs of the same or a similar form taken by 
Harmon Craig, Scripps Institution of Oceanography (SIO) from ALVIN at a vent system 
at 10°57'N, 103°41'W have been seen by us, and Robert R. Hessler, SIO, has seen 
small individuals at 13°N from CYAN A. No bythitid fish has yet been seen at 2rN 
despite extensive observations. As of this writing specimens have not been captured, 
and the species is not further discussed in the present paper. 

The Zoarcidae, or eelpout family, also includes species of vent-associated fishes. 
At the Galapagos Rift vent area, eelpouts are cryptic and have been questionably 
identified from ALVIN only twice; however, two species are common in time-lapse 
photographs (Cohen and Haedrich 1983). Two specimens have been captured, one a 
relatively large, light-brown individual taken in a trap; the other, a smaller, pale fish, 
was washed from ALVIN after the submersible surfaced. The two specimens have very 
similar counts and head pore patterns. At 21°N a pale zoarcid was observed to be 
common in warm water. Several specimens were captured incidentally, and enzyme 
activities were described by Hand and Somcro (1983). We have also examined two 
pale specimens trapped among pogonophorans by a French expedition working at vents 
near 13°N, where eelpouts were common. 

Recently a sulfide-rich area with a community having many features of the Pacific 
vent communities has been discovered off the Florida escarpment (Paull et al. 1984). 
Color photographs seen by us show an elongate, pale fish on the bottom, certainly a 
zoarcid, and with a considerable general resemblance to our new genus. However, 
neither specimens nor close-up pictures are available. 



72 



SUPRAORBITAL 
PORES 12 



NOSTRIL 




POSTORBITAL PORE 1 



SUBORBITAL CANAL 
PORES 1-6 



SUBORBITAL 
OSSIFICATIONS 



1 mm 

Figure 1 . Thermarces cerberus new species (SI082-46). Lateral view of left side of head showing suborbital 
canal and ossifications (posterior ossification actually present on right side only), suborbital pores, and first 
preorbital pore. 



We have been unable to place our zoarcid material in a genus or species. The 
specimens cannot be included in any genus as presently defined. We have had more 
success in referring our material with the aid of a Ph.D. dissertation by Eric Anderson 
(1984). 

Although all eight of our specimens have approximately similar counts, one is 
notably different from the others in its light-brown color, and in having scales, vestigial 
pelvic fins, and a long tail (62% SL). This specimen was captured in a baited trap and 
photographed in the general area of one of the Galapagos vents where, although cryptic 
in habit, the species is apparently abundant (Cohen and Haedrich 1983). It may rep- 
resent an undescribed species of Pachycara Zugmayer, 1911 (M. E. Anderson personal 
communication). Because this species is not known to occur in warm water and because 
our single example is in poor condition, we are not able to comment further upon it. 

Our other seven specimens, all directly or indirectly associated with warm water, 
are pale, lack scales and pelvic fins, and have short tails (48.9 to 54.8% SL). These 
fishes do not fall within the bounds of any zoarcid genus as defined by Anderson ( 1 984), 
and we place them in a new genus that agrees in part with Pachycara. The measurements 
as given in Table I are self-explanatory. Head-pore terminology is that of Gosztonyi 
( 1 977). Fin rays and vertebrae were determined from radiographs. Description of cranial 
osteology is based on a trypsin-cleared preparation stained for cartilage and bone. 

Thermarces new genus 

Type species. — Thermarces cerberus, new species. 

Diagnosis. —Lycodine zoarcids with precaudal vertebrae 29-31, total vertebrae. 



73 



HYOIVIANDIBULAR 




MESOPTERYGOID 



SYMPLECTIC 



ECTOPTERYGOID 



QUADRATE 



1 mm 



Figure 2. Thermarces cerberus new species (SI082-46). Lateral view of right suspensorium. 

94-97; suborbital bones 1 or 2; ectopterygoid in contact with a small area of the 
quadrate, and mesopterygoid with no contact; pectoral radials 4, unossified; postcleith- 
rum lacking; infrapharyngobranchials 2; pelvic bone and fin rays lacking; no scales, no 
body lateral line. 

Description. — Body relatively deep, 9.8-1 3.4% standard length; tail relatively short, 
48.9-55% standard length; snout blunt and rounded, with subterminal jaws. Scales 
lacking. 

Ventral face of dentary lacking cartilaginous ridges (mental crests of Anderson 
1984). Pseudobranch reduced to a continuous membrane with several small nubbins. 
Infrapharyngobranchials with ossified tooth plates on arches two and three only. 

Suborbital bones one or two (Fig. 1), no cartilaginous elements; a slight, irregular 
ossification roofs the sensory canal dorsal to pore number 2. There is also a slight 
ossification on the medial wall of the canal midway between pores 3 and 4 on the right 
side of the specimen but not on the left (shown on the left in Fig. 1 ). 

Abdominal vertebrae 29-32; total vertebrae 94-97. 



PARIETAL 



FRONTAL 



MESETHMOID 




SUPRAOCCIPITAL 
EPIOTIC 

PTEROTIC 
EXOCCIPITAL 



BASIOCCIPITAL 



VOMER 



LATERAL 
ETHMOID 



TRIGEMINOFACIALIS 
FORAMEN 



1 mm 



Figure 3. Thermarces cerberus new species (SI082-46). Lateral view of left side of cranium. Ossification 
is thin, location of sutures approximate and based on a single specimen. 



74 




Figure 4. Thermarces cerberus new species, holotype. 



Ectopterygoid a slender splint anteriorly, expanded posterioriy but in contact with 
no more than the dorsal section of the leading edge of the quadrate (Fig. 2). Meso- 
pterygoid represented by a long, tissue-thin ossification in a band of cartilage, narrowly 
connected with metapterygoid posteriorly. Nearly all of dorsal margin of quadrate 
bordered by cartilage, except at the extreme anterior end where a narrow, ossified lappet 
extends posteriorly from the ectopterygoid. 

Pectoral girdle with cleithrum well-ossified, scapula and coracoid poorly ossified 
and tissue-thin, radials unossified and scarcely visible; postcleithrum lacking. 

Pelvic fin rays and pelvic bone lacking. 

Ascending wing of parasphenoid not reaching mid-height of trigeminofacialis fo- 
ramen, pterosphenoid not separating frontal and parasphenoid (Fig. 3). 

Etymology. —The name Thermarces is derived from the Greek thermos, heat, and 
the generic name Zoarces, the type genus of the family. 

Discussion. —y\.osX of the diagnostic characters presented above are reductional. 
Thermarces could be a derivative of a Pachycara-\\\iQ fish. It shares with Pachycara 
the following characters: body robust; tail short; mental crests absent; parasphenoid 
wing below mid-height of trigeminofacialis foramen; abdominal vertebrae 26-32; pseu- 
dobranch filaments 0-6; head blunt and rounded (characters for Pachycara from An- 
derson 1984). 

Thermarces cerberus new species 
Figures 4, 5 

Description. —CounXs and measurements are given in Table I. Head and body 
laterally compressed, body width contained about twice in depth at mid-trunk, about 
7 in depth just before caudal fin. Head and trunk slightly shorter than tail. Head 1.8 
in trunk (1.4 in small Galapagos specimen). Eye small, covered by skin, 4.5-5 in snout 
(4 in smallest specimen). Mouth terminal, moderately oblique, anterior tip of mandible 
well above mandibular symphysis; jaws subequal. Lips distinct, thick and fleshy, con- 
tinuous and smooth. Oral valves obsolete. Nostril in a short tube, which does not reach 
upper lip. Head pores large and conspicuous. Occipital pores absent, suborbital 6, 
supraorbital 2, postorbital 2, preopercular 4, mandibular 4 (symphysial pores closely 
opposed). 

Teeth in both jaws stout, conical and pointed. Dentary teeth in a triserial patch 



75 






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76 






Figure 5. Otoliths of Thermarces cerberus new species, from a 244 mm paratype, SI08 1-155. Upper, right 
otolith, inner face; lower, left otolith, outer face. 

Figure 7. Thermarces cerberus in situ near the type locality. In the foreground the vestimentiferan worm 
Riftia and part of the submersible ALVIN. 

Figure 8. Otolith of Thermarces cerberus, same data as Figure 5, viewed in transmitted light. 



anteriorly and a single posterior row. Teeth of upper jaw uniserial except for a few 
slightly enlarged teeth in outer row at symphysis. Vomer with patch of about 15 teeth, 
autopalatines with a row of about a dozen teeth. Teeth in roof of mouth about as large 
as largest jaw teeth. Gill openings relatively unrestricted, ending about at level of lower 



77 




Figure 6. Thermarces andersoni new species, holotype. 



end of pectoral base, about 3 in head. Isthmus width shghtly less than gill-opening 
length. Gill rakers 1-1-14 on first arch, rakers short but flattened, some on ceratobran- 
chial with pair of teeth at tip. Gill filaments well-developed, about 3 in snout. Pectoral 
fin small, rounded, its base about 2.2 in gill opening, its length about 0.8 in snout. 
Pectoral rays covered by thick skin. Vertical fins relatively well-developed, covered by 
skin. Dorsal origin obscure, on radiographs seen to be between sixth and seventh 
vertebrae. Caudal pointed, with 6 + 5 rays. Dorsal and anal rays mostly unbranched. 
Color in situ pale. Freshly dead individuals white with pink suffusion, dark peritoneum 
showing through body wall. Holotype with a series of dark flecks along dorsum, be- 
ginning just behind head. Paratypes from SI08 1-155 with a few melanophores scattered 
on the dorsum. Body otherwise immaculate. Peritoneum dusky. 

£'?vmo/o^.— Cerberus is the dog-like monster which in Greek mythology guards 
the gates of Hades. 

Holotype. —S\0^\-\55, a 259 mm SL 9 with ripening eggs. Taken off" Mexico at 
20°5rN, 109°04'W, at a hydrothermal vent site in 2600 m by Expedition 'Tluto," leg 
4, ALVIN Dive 1157 on 21 November 1981. The specimen was found accidentally 
trapped in the conning tower of the submersible ALVIN, and returned to Scripps 
Institution of Oceanography by Harmon Craig. 

Paratypes. —S\0^\-\55, collected with, and bearing the same data as the holotype 
2(181-244). Natural History Museum of Los Angeles County, LACM43719-1, formerly 
SI082-45, off'Mexico at 20°49.05'N, 109°06.40'W at a hydrothermal vent site, at 2600 
m on 20 April 1982 by Expedition "Oasis," station 1214-4. Found in the conning 
tower of the submersible ALVIN and returned to SIO by Robert R. Hessler. 

Additional material. —SIOS2-46. Same data as S1082-45, but taken on 14 May 
1982 from a pipe draining sail of ALVIN. 1, head and part of trunk. Cleared and 



78 

stained. LACM43531-1, Galapagos Rift zone, from conning tower of ALVIN, 22 Au- 
gust 1977.1(127). 

Thermarces andersoni new species 
Figure 6 

Description.— CownXs and measurements are given in Table 1. Thermarces an- 
dersoni is similar to T. cerberus in most respects, and characters in agreement are not 
repeated here. Head and body compressed, but robust, head 1.4 in trunk. Eye small 
3.3-3.5 in snout. Gill opening 2.75 in head in holotype, 3.0 in paratype. Isthmus width 
equal to gill opening. Most dorsal and anal rays branched, dorsal rays branched for 
about one-half their length, anal rays branched for one-third to one-half their length. 

Color of freshly dead individuals pale, belly dark. Body, fins and dorsal part of 
head flecked and mottled with brown. Peritoneum of holotype pale, that of paratype 
blotched with pigment, mostly dorsally. Photographs of three fresh individuals supplied 
by R. R. Hessler show a dark belly, indicating a dark peritoneum. 

Holotype.— MusQum. National d'Histoire Naturelle, MNHN 1985-400, CENTOB, 
BIOCYATHERM, DIVE 82-35. A 272 mm $ taken in an amphipod trap at 1 2°48.85'N, 
103°56.60'W on 12 March 1982 at 2620 m depth, by the submersible CYANA. 

Paratype.— MNWN 1985-401, a 249 mm 6 taken with the holotype. 

Etymology. — Earned for M. Eric Anderson, student of zoarcids, who freely shared 
his knowledge with us. 

Comparison. — Thermarces andersoni is similar to T. cerberus in many respects, 
including meristics. It differs most notably in the more robust head and body, a larger 
eye, and in coloration. Also, there appears to be a difference in number of anal, and 
possibly caudal, rays (Table 1). 

Due to the small number of available specimens, the morphological differences, 
though readily apparent, are difficult to establish and validate through measurement. 
However, Table 1 shows that the values for Body Width and Head Depth for the 
Thermarces andersoni specimens are higher, and well outside the range for the five 
specimens of T. cerberus. The eye of the types of T. andersoni is proportionately larger 
than in the comparably sized specimens of T. cerberus. The smallest specimen of T. 
cerberus (127 mm) does have an eye which is proportionately as large as that of the 
much larger type specimens of T. andersoni, but typically the eye exhibits negative 
allometry. 

The specimens of Thermarces andersoni are much more heavily pigmented, es- 
pecially about the head, body and fins, than are those of T. cerberus, which are almost 
completely colorless, with at most a few flecks of pigment on the dorsum. 

The differences in coloration and body shape are not sexual, as males and females 
are represented in both species. Nor is it likely that the andersoni types represent the 
chance capture of two rare variants. Color slides of three additional Thermarces an- 
dersoni from 1 3°N supplied by Robert Hessler show individuals closely resembling the 
types in having a robust body and being relatively heavily pigmented. It thus appears 
that the type material of T. andersoni fairly represents the population at 1 3°N. 

The two nominal species will probably be found to differ also in number of anal 
rays. The range for Thermarces cerberus is 66-69, x 67.6, SD 1.3. The holotype of T. 
andersoni has 64 and the paratype 65. The available material also differs in number 
of caudal rays, 10 in T. andersoni and 1 1 in 7". cerberus. 

Natural History 

Individuals of Thermarces cerberus are commonly seen near vents, either in the 
open, or nestled among mussels or clams. Their relative abundance in some places is 
shown in Figure 7. Hand and Somero (1983) have noted that the activity of the enzymes 
lactate dehydrogenase and pyruvate kinase in white muscle of T. cerberus is the highest 
thus far measured for a deepsea fish, and "within the range noted for many shallow- 



79 



living demersal species." The ability to sustain a high metabolic activity was attributed 
to the food-rich environment of the vents. 

We examined the stomach contents of two Thermarces cerberus. One contained 
5 white trochiform snails (undescribed) about 7 mm diameter. The other contained 
two lysionassid amphipods (undescribed), and a moss-green material with a strong 
sulfurous smell that proved to be from the trophosome of the pogonophoran Riftia 
pachyptila. The trophosome contains a large number of symbiotic sulfur-oxidizing 
bacteria (Cavanaugh 1983). A radiograph of the holotype shows that there are two 
snails in the intestine and another in the pharynx. 

The pogonophoran is in a stout tube which should deny small fishes access to its 
soft parts. However, the submersible ALVIN had been lying on the bottom while an 
experiment was being performed and had undoubtedly crushed numerous worm tubes 
making an otherwise inaccessible food available. That a probably unaccustomed prey 
was taken indicates a generalized feeding habit. Moreover the fact that Riftia, which 
may have concentrations of up to 1.1 mM hydrogen sulfide in the blood (Arp and 
Childress 1983) was eaten, indicates a considerable tolerance for this poison by Ther- 
marces cerberus. 

There is less information available concerning Thermarces andersoni. The types 
were trap-caught, and the stomach of the paratype proved to be empty. The trap entered 
was baited with fish, which may also indicate a generalized food habit for this species. 

Otoliths were removed from four specimens of Thermarces cerberus. All show 
clear and opaque bands (Fig. 8). Given the limited nature of the material it would be 
premature to ascribe significance to the banding, but it is suggestive that otoliths from 
the three large specimens (250, 244, 239 mm) have two clear zones and that of a smaller 
one (181 mm) has but one. 

Acknowledgments 

The following individuals provided information, specimens, or both: Eric Anderson, 
California Academy of Sciences; Roberta Baldwin, SIO; John Corliss, Oregon State 
University; Harmon Craig, SIO; Daniel Desbruyeres, IFREMER, CENTOB, Brest; 
John Edmond, Massachusetts Institute of Technology; Richard Haedrich, Memorial 
University of Newfoundland; Robert Hessler, SIO; Emory Kristof, National Geographic 
Society; Charles Paull, SIO; John Porteus, Woods Hole Oceanographic Institution; 
Michel Segonzac, CENTOB, Brest; F. N. Spiess, SIO. We thank them all. 

Material of Thermarces andersoni was supplied by the Centre National de Tri 
d'Oceanographie Biologique (CENTOB, Brest) and came from mission BIOACYTHERM, 
organized by the IFREMER (Centre de Brest). 

Literature Cited 



Anderson, M. E. 1984. On the anatomy and phy- 
logeny of Zoarcidae (Teleostei: Perciformes). 
Ph.D. Dissertation. School of Marine Science, 
The College of William and Mary in Virginia. 

Arp, A. J., and J. J.Childress. 1983. Sulfide bind- 
ing by the blood of the hydrothermal vent tube 
worm Riftia pachyptila. Science 213:342-344. 

Cavanaugh, C. M. 1983. Symbiotic chemauto- 
trophic bacteria in marine invertebrates. Na- 
ture 320:58-61. 

Cohen, D. M., and R. L. Haedrich. 1983. The fish 
fauna of the Galapagos thermal vent system. 
Deep-Sea Research. 30(4A):37 1-379. 

, and J. G. Nielsen. 1978. Guide to the iden- 
tification of genera of the fish order Ophidi- 
iformes with a tentative classification of the 
order. National Oceanic and Atmospheric 
Administration Tech. Rept., National Marine 
Fisheries Service Circular 417:1-72. 



Gosztonyi, A. E. 1977. Results of the research 
cruise of the FRV "Walter Herwig" to South 
America XLVIII. Revision of the South Amer- 
ican Zoarcidae (Osteichthys, Blennioidei), with 
the description of three new genera and five 
new species. Arch. Fisch.-Wiss. 27(3): 19 1-249. 

Hand, S. C, and G. N. Somero. 1983. Energy 
metabolism pathways of hydrothermal vent 
animals: adaptations to a food-rich and sulfide- 
rich deep-sea environment. Biological Bulletin 
165:167-181. 

Paull, C. K., B. Hecker, R. Commeau, R. P. Free- 
man-Lynde, C. Neumann, W. P. Corso, S. Go- 
lubic, J. E. Hook, E. Sikes, and J. Curray. 1 984. 
Biological communities at the Florida escarp- 
ment resemble hydrothermal vent taxa. Sci- 
ence 226(4677):965-967. 




TRANSACTIONS 
-, OF THE SAN DIEGO 

.^RARY SOCIETY OF 

^' "^^ NATURAL HISTORY 

MAR ^ 6 1986 

li ARX/AvRD 
J ,y Volume 21 Number 5 pp. 81-87 24 February 1986 



A lectotype for Dinapate wrightii Horn, the giant palm-borer, and 
description of a new species of Dinapate from eastern Mexico 
(Coleoptera: Bostrichidae) 

Kenneth W. Cooper 

Department of Biology, University of California, Riverside, California 92521 USA 

Abstract. A lectotype is designated for Dinapate wrightii Horn. It is emphasized that Horn's type 
series consists entirely of fragmentary, disarticulated specimens from which Horn drew a composite 
description. Only three of these very imperfect syntypes appear to have been preserved. A second 
species (Dinapate hughleechi new species) has been found infesting palms [Sabal texanum (Cook) Becc] 
in east-central Mexico. Its description, secondary sexual characteristics, and taxonomic separation from 
D. wrightii are presented. 

Resumen. Un lectotipo para Dinapate wrightii Horn, el baranillo gigante de las palmeras y una 
descripcion de una nueva especie de Dinapate del este de Mexico (Coleoptera: Bostrichidae). Un 
lectotipo esta designado por Dinapate wrightii Horn. Se nota que el tipo Horn consiste solamente de 
especimenes fragmentarios y desarticulados de los cuales Horn inferio una descripcion compuesta. 
Parece que solamente tres de estos sintipos se han preservados. Un segunda especies {Dinapate hugh- 
leechi new species) se ha encontrado infestando palmas [Sabal texanum (Cook) Becc] en el este-central 
de Mexico. Su descripcion, sus rasgos sexuales secundarios y la separacion taxonomica de D. wrightii 
se exponen en el texto. 

Introduction 

Dinapate (Horn 1 886a) until now has been a monotypic genus, with its sole species 
a subject of unusual interest and speculation ever since its discovery. It was set apart 
on morphological grounds from other bostrichids within a tribe Dinapatinae (Lesne 
1910), later the subtribe Dinapatina (Lesne 1938), of which it has remained the sole 
representative. Generic diagnoses are to be found in Horn (1886), Lesne (1909) and 
Fisher (1950). 

In keeping with its taxonomic isolation, there are distinctive aspects of its biology. 
Almost all bostrichids are polyphagous, feeding upon ligneous tissues of a wide range 
of plants (Lesne 1911). Few bostrichids attack living plant tissue, and only 5 other 
species among the 400-500 known Bostrichinae include palms or their parts among 
the beetles' ordinarily diverse sources of food (Lepesme 1947). Dinapate wrightii is, 
therefore, markedly unusual among bostrichids. Not only does it regularly attack living 
palms, but it would appear unique by being restricted in its development to but one 
species, the California Fan Palm, Washingtonia filifera Wendl. (Baker 1971). The 
known distribution of D. wrightii, southern California to Catavina in Baja California 
Norte (Michelbacher and Ross 1 939), lies entirely within the natural range of W. filifera. 
Dinapate is also the giant among bostrichids, by far the largest known, up to 60 mm + 
in length from the anterior margin of the pronotum to the apices of the elytra. It thus 
reaches nearly twice the length and 6.6 times the volume of the second largest bostrichid, 
Apate terebrans Pallas (to 32 mm, Lesne 1909), a native of tropical Africa and a miner 
oi Acacia and its relatives (Lesne 1924). 

The purpose of this paper is to designate a lectotype for Dinapate wrightii Horn 



82 

and to describe a new species of Dinapate from eastern mainland Mexico that is also 
a palm miner. A second study will provide information and new findings on the general 
biology, host range, and distribution of Dinapate species, as well as critical comment 
on the early history surrounding William Greenwood Wright's discovery of the beetle 
bearing his name— a paradoxical record. 

Designation of a Lectotype 

The George H. Horn collection, Museum of Comparative Zoology, Harvard Uni- 
versity, contains three articulated female specimens labelled as follows: 

(1) Lectotype 3560/ Dinapate wrightii Horn. Moj. Des.; 

(2) Cal./Para-type 3560-2; 

(3) N.J./Hom Coll. H 10, 1 59 [the catalog number in Henshaw's third supplement 
(1895)]. 

In addition there is a fourth "mock-up" of Dinapate wrightii made from fragments of 
a male, blackened cork and beeswax, labelled: Para-type 3560-3. 

When Horn (1886a) described D. wrightii he thanked Wright, the collector, "For 
the fragments in my possession," and his descriptions and illustrations (plate I) were 
prepared from fragments of "several specimens" (Horn 1885, 1886a; see also Schwarz 
1899). Among these there were at least more than one representation of the female sex, 
for he stated ". . . the smaller specimens are females" (Horn 1886a). Where are the 
remaining fragments to be found of two or more females that Horn possessed? 

There are four additional specimens of Z). wrightii in the John L. Leconte collection 
at the Museum of Comparative Zoology, necessarily placed there after Leconte's death 
in 1883 (and most certainly by Horn). Two of these are fragmented. One is a female 
without labels, consisting of an elytron, abdominal venter, meso- and metastema, and 
legs; the other is represented by a pair of male elytra mounted on a beetle-shaped piece 
of wood on a pin, and is also without labels. Very likely these two are from the sets of 
fragments from which Horn drew his descriptions and illustrations. I have been unable 
to discover whether a fourth disarticulated specimen, or still more, attributable to 
Horn's original series now exists. If so, the specimen or specimens are neither at Harvard 
nor at the Academy of Natural Sciences in Philadelphia in which Horn's collection was 
originally housed. 

Horn's article appeared in the January 1886 issue of the Transactions of the 
American Entomological Society, but that issue almost certainly was published at some 
unrecorded later month. It was in fact first approved for publication on Jan. 28, 1886 
as stated in the publication register of the American Entomological Society. It is thus 
possible that Horn studied, but did not mount, keep, or explicitly mention, additional 
fragments of the beetle possibly received along with "... the fragment of tree trunk 
sent several months ago [early in June?] by W. G. Wright" (Horn 1886^). Later, in 
early September of 1 886 and certainly after publication of Horn's description (for Horn 
makes no mention there of having seen an intact specimen), an unspecified number of 
Dinapate emerged from the fragment of trunk. With one possible exception, they were 
females, no more than five or six in number, and assuredly are the only complete 
specimens mentioned by Horn in his writings. Some of them at least are among the 
intact specimens in the Horn and Leconte collections. Their possession made it un- 
necessary for Horn to retain in his collection any fragmented specimens. Why then did 
he keep "Para-type 3560-3"? Almost certainly that specimen, a male, was the best of 
those used by Horn when describing Dinapate wrightii, and had value to him for that 
reason. 

In any case, the three fragmented specimens mentioned above certainly served as 
pari of Horn's descriptive material and are syntypes, whereas none of the intact spec- 
imens in the Horn and Leconte collections so served, nor did the female possessed by 
the M seum National d'Histoire Naturelle, Paris, a gift from Horn in 1888. So what 
is to be Tiade of the specimen in the Horn collection that is in fact labelled: "Lectotype 
3560"? 



83 

Horn never formally designated a type, and I have been informed (by Mr. P. J. 
Johnson and through Dr. A. F. Newton, ]r.— personal communication) that "When 
the Horn collection was still in Philadelphia all the unique or first-specimen-of-the- 
series specimens were labelled with cataloging numbers. Unfortunately the labels used 
were printed as lectotype labels, and to date no lectotype has been designated." 

For the reasons given, the only specimen of the series now in the Horn collection 
that contributed to the description of Dinapate is the male mock-up bearing the sole 
label: Para-type 3560-3. That specimen is designated here as the lectotype; the frag- 
mented female and mounted male elytra in the Leconte collection are, accordingly, 
paralectotypes. 

A New Species of Dinapate 

Mr. Hugh B. Leech, commenting in June 1984 on a draft of a manuscript devoted 
to the biology and history o^ Dinapate wrightii, stated that Dinapate is also to be found 
in eastern, mainland Mexico, about 1040 km E of Baja California, where he and Dr. 
E. S. Ross had dug a partially disarticulated female from a palm log. That specimen 
appears very similar to the female of D. wrightii insofar as the remains are concerned, 
but differs noticeably by having an unusual amount of long hair on the frons. Then, 
on Dec. 6, 1984, Dr. Ross Amett informed me that specimens of Dinapate, collected 
in 1965 from eastern Mexico and thought to be a new species, are in the Florida State 
Collection of Arthropods, Gainesville. Through his kindness, and the generosity of 
Drs. Robert Woodruff and Eugene J. Gerberg, I have been permitted to examine and 
study the three female specimens. Finally, and most fortunately, the California Academy 
of Sciences possesses a male, collected by Dr. E. S. Ross in 1946, that I have been 
permitted to include in this study. The five specimens do indeed represent a species 
markedly similar in size and general appearance to smaller specimens of D. wrightii, 
yet differ notably in many features that become striking only in aggregate. 

The color names having a numerical notation in the following description are 
represented by color swatches portrayed and described in Smithe (1974-1981). 

Dinapate hughleechi new species 
(Figures lA, IC, IE, II, IJ) 

Description. —Length (anterior pronotal margin to elytral apex) 35-40 mm; width 
at humeral umbone 12.7-14.4 mm. Head, body above, legs, palps, scape and funicular 
joints of antennae dark, blackish to warm sepia (221 A); expanded portions of antennal 
club warm sepia to burnt umber (22); pubescence long and abundant on head, mouth- 
parts, tibiae, sternum and abdomen, ferrugino-testaceous to buff (24). 

Head, including frontal furrow and clypeal suture, similar to D. wrightii, except 
sides of clypeus, frons (especially bordering eyes), and upper occiput with abundant 
long pubescence (may be diminished or lost with age). Antennae with 8th joint forming 
a wide angle (80°±) above, length 10th joint about 1.8 x greatest breadth (Fig. IE). 

Pronotum slightly wider than long (m w/1 = 1.9, range 1.07-1.10), similar to D. 
wrightii with sparse, long pubescence along margins and flanks, strong, rasp-like pro- 
jections anteriorly and laterally. 

Scutellum concave above. 

Elytra at humeral umbone broader than pronotum at widest (mean humeral width/ 
pronot. w. = 1.18, range 1 .06-1 .27); humeral umbone coarsely, deeply wrinkled, incised 
and reticulated; sides subparallel; surface with 6 low, broad costae, crenulated along 
lengths by angular, marginal punctures, disposed as in D. wrightii (Figs. IG, IH), 
corresponding with the customary main longitudinal tracheae of the coleopterous wing 
pad: costa 1 (Sc?) subparallel to fluted marginal bead, 2 and 3 (R and M?) arising from 
below and behind the umbone, 3 very weak, obsolescent along most of length, 4 (Cu?), 
5 (PCu?), and 6 ("A"), the sutural costa; costa 2 terminates below the outer broad 
tumidity ("outer tubercle") above the declivity, and 3 and 4 terminate on that eminence 
(Figs. IG, IH); 1 and 2 contact and then diverge in apical third (Fig. IH), basally 



84 






  III 





- w» try -r w.«f-».f .V." r.*'.*".««.'"T~^''^"v^;a^ v\. 

^ — — -^ ^»».'r.i>.-»-.r'.rr;-^''-'^'^"*"?^»»- 





6 

5 



3 
2 



5 
4 
3 
2 






Figure 1. Profile of elytral tubercles and declivities of (A) D. hughleechi male, (B) D. whghtii male, (C) Z). 
hughleechi female, (D) D. whghtii female, with 10 mm scale for Figs. A-D. Fig. (E) antenna of Z). hughleechi, 
with 3 mm scale, (F) of D. whghtii, to same scale as E. Fig. (G) left elytron of D. whghtii from above, (H) 
same, obliquely from side (numbers to right of both figures designate costae), scale equals 10 mm. Fig. (I) 
anterior face of hind tibia of female D. hughleechi and (J) male; (K) same, of D. whghtii female and (L) 
male, with 5 mm scale for Figs. I-L. 



enclosing a long subcostal cell; 5 terminates on the narrow, raised inner tubercle above 
the declivity (Figs. 1 G, 1 H); 6 extends forward along the suture, diverging anteriorly 
somewhat before the apex of the scutellum, margins raised and somewhat widened 
along declivity. Dorsal intervals closely, coarsely punctate, the raised polished interstic- 



85 

es giving the appearance of being irregularly linked; elylral apices triangularly divergent, 
more or less sinuate laterally. 

Legs subequal in length; fore-tarsus (not including claws) shorter than tibia; mid- 
and hind-tarsi subequal to their tibiae; tibiae flattened, with 8-12 blunt, subtriangular 
teeth on outer margin (Figs. II, IJ); posterior surface of anterior tibia with 2-4 broadly- 
based, small denticles (m = 2.8); anterior surface of mid-tibia with 6-13 (m = 8.8), of 
hind-tibia with 0-10 (m = 5.3) blunt, low-lying tubercles, more or less in lines, 1-3 
tubercles in breadth along apical 4/5ths of tibiae (Figs, II, IJ); asymmetry in numbers 
and disposition of tubercles and marginal teeth of right and left tibiae the rule; a 
conspicuous, smooth, polished area behind anterior apical spine and outer apical tooth 
of hind-tibia (Figs. II, IJ), a smaller, more irregular area on mid-tibia; posterior surfaces 
of mid- and hind-tibiae with abundant, long recumbent hair directed apically. 

Pro-, meso-, metastemum and abdominal stemites finely asperate at bases of hairs; 
metastemum appears strigate in part, metepistemum finely shagreened. Fifth visible 
abdominal sternum truncate or slightly concave on apical margin, marginate, with the 
margin broadened and polished along medial fourth. 

Secondary sexual characteristics. —Male similar in size and overall morphology to 
female but differing as follows: clypeus and front of head coarsely punctate, punctures 
separated by a diameter or more (clypeus and frons of female closely and conspicuously 
asperate); pronotal rasp-like tubercles on flanks and anterior dorsum of male more 
strongly developed; inner ("sutural") posterior tubercle of elytron pointed, noticeably 
projecting above elytral declivity but blunt, not or barely projecting in female {cf. Figs. 
lA, IC); declivity shining, sparsely punctate (in female dull, densely rugose and as- 
perate); tibiae broader apically (cf. Figs. II, IJ), with dense long hairs on posterior 
surfaces of mid- and hind-tibiae, those of hind-tibiae very dense (inner surfaces of mid- 
and hind-tibiae of female alike, hairs abundant but not dense); posterior surfaces of 
joints 2-4 of mid-tarsi (and probably also of hind-tarsi, as is the case in D. wrightii) 
with posteriorly-directed fans of long, stiff, hairs (female with relatively sparse, very 
short hairs); hairs on disc of the 5th visible abdominal stemite not abruptly longer and 
nearly erect (abruptly longer and erect or suberect in female). It is to be noted that a 
hairy frons, while common among female Bostrichinae, is an uncommon attribute of 
males (Lesne 1924). 

Etymology.— The specific epithet hughleechi is in honor of Mr. Hugh B. Leech, 
now Curator Emeritus of Coleoptera at the California Academy of Sciences who, 
over very many years, has generously helped, counseled, and befriended countless 
coleopterists, among whom I have had the great good fortune to be one. 

Holotype. —Male, 37.5 mm long, from Mexico, State of Tamaulipas, 1 5 miles west 
of Antigua Morelos [hence, near Nuevo Morelos— see below] ex palm log, Nov. 10, 
1946, E. S. Ross collector. Collection of the California Academy of Sciences, San 
Francisco, type number 15290. The type was evidently taken from the log as a dead 
specimen; it is nevertheless the individual in best condition of all 5 specimens available. 
It lacks palpi, joints 9-10 of both antennae, the right mid-tibia and tarsus, and both 
hind tarsi. 

Allotype. —Female, 35.4 mm long; from Mexico, State of San Luis Potosi, El Salto 
Falls [Salto de Agua], elevation 402 m (1320 ft), April 22, 1965, E. M. Collins, Jr., 
collector. Florida State Collection of Arthropods, Gainesville. The allotype lacks the 
right maxillary palp, both antennae beyond joints 2, right anterior tarsal joints 4-5, 
and the left posterior tarsus. 

Paratypes. —One female, Mexico, State of Tamaulipas, near Nuevo Morelos, dead 
when collected, in poor condition, ex log of Sabal texana (Cook) Becc. (determined as 
S. mexicana Cook, a junior synonym [Bailey 1961], by J. F. Hart of Ciudad Valles, 
San Luis Potosi, Mexico), Nov. 18, 1948, Hugh B. Leech and E. S. Ross collectors, 
California Academy of Sciences. 

Two additional females, of same label data as the allotype, Florida State Collection 
of Arthropods, Gainesville, lacking antennae, one or more palps and legs. 

Comment. —The three specimens from the Florida State Collection of Arthropods 



86 

came loose during shipment to me. The broken palps, antennae, legs, and parts of legs 
were recovered; though suitable for study, they cannot with certainty be matched to 
individual specimens. They are now collectively preserved in a gelatin capsule accom- 
panying the specimens, labelled and mounted on a pin. 

Recognition ofD. hughleechi.— Though not easily distinguished from all specimens 
of/), wrightii without the use of a lens, D. hughleechi is nevertheless strikingly different. 
In descending order of ease in determination, it may be separated by (1) the concavity 
of its scutellar disc (convex in D. wrightii), (2) the large, subrectangular, slightly convex, 
polished apical area on the anterior face of the hind tibia (a lesser one on the mid- 
tibia) {cf. Figs. II, IJ, with IK, IL), (3) the abundant long hairs on clypeus, frons and 
occiput, recognizable by their stumps when abraded (in D. wrightii there are few long 
hairs on the clypeus or supraorbitally, and the hairs of the occiput, which are rarely 
lost, are numerous but inconspicuous, very short, fine and decumbent), (4) the strongly 
wrinkled and deeply incised reticulation of the humeral umbone, (5) the inner and 
outer elytral tubercles above the declivity are less well-developed {cf. Figs. 1 A, 1 C with 
IB, ID, IG, IH), (6) first joint of the antennal club (joint 8) has its superior dorsal 
angle >78° (in D. wrightii ca. 65°, cf. Figs. IE, IF), (7) the outer marginal teeth of the 
tibiae are broader, blunter (m angle = 41°, range 31°-51°, Figs. II, IJ; in D. wrightii 
m = 29°, range 25°-37°, Figs. IK, IL; also Lesne, 1909, pi. 14, figs. 3, 4), and (8) the 
tubercles on the anterior face of the mid- and hind-tibiae, and posterior face of the 
anterior tibia, are decumbent and blunt (spinulose and suberect in D. wrightii; cf Figs. 
11, IJ with IK, IL). 

The costae on the flanks (especially costa 3) of the elytra in D. hughleechi are not so 
strongly defined, although I would expect some individuals in a larger sample to have 
them equally developed to those of £>. wrightii. Horn (1886) overlooked costae 2, 3 
and 6 when describing D. wrightii, and Fisher (1950) noted only "four or five obtusely 
rounded, longitudinal costae." Admittedly all six costae are not definable at a glance. 
But if an elytron is removed from a specimen, and a fine pin is passed through each 
of the six tracheae running lengthwise and close to the inner surface, the resulting six 
(pin-) holes on the outer surface of the elytron immediately flag the costae. Once seen 
in this manner, they can be made out in all specimens of both species seen by me {n = 
5 and 76 respectively) and correspond precisely with those figured by Lesne (1898:446, 
fig. 49) for Bostrichus capucinus Linn. 

Diagnosis of the genus Dinapate.— Fisher's (1950, pp. 51-52) fine diagnosis re- 
quires only three emendations now that a second species is known: (1) "Scutellum 
small, quadrate, strongly elevated:— delete "strongly elevated"; (2) "tibiae . . . armed 
on exterior margins with a few large, triangular teeth "—delete "few"; (3) ""posterior 
tarsi as long as tibiae"— replace with: mid and posterior tarsi subequal to tibiae. 

Acknowledgments 

Special gratitude is extended to Mr. Hugh B. Leech who first called my attention to 
the occurrence of Dinapate in mainland Mexico. I am indebted to Drs. David Kav- 
enaugh and Paul Amaud for loan of the holotypic male and for information concerning 
W. G. Wright's specimens and collecting records; to Mr. Saul Frommer, of the Uni- 
versity of California at Riverside, for use of the specimens in his custody; to Drs. Ross 
Amett and Robert Woodruff'of the Florida State Collection of Arthropods, Gainesville, 
and to their colleague Dr. Eugene F. Gerberg, for their generous suggestion that I describe 
the specimens in their care. To Dr. Alfred F. Newton, Jr., Curatorial Associate in 
Entomology at Harvard University, and to Mr. Paul J. Johnson (now at the University 
of Idaho), I am greatly indebted for their detailed and cordial responses to my many 
questions concerning specimens of Dinapate in the collections of the Museum of Com- 
parative Zoology. Dr. Jean J. Menier, of the Museum Natural d'Histoire Naturelle, 
Paris, obligingly sent me accession records of the specimen of Dinapate used by Lesne 
in erecting the tribe Dinapatinae. I thank Ms. Carol M. Spawn, Manuscript and Archives 
Librarian of the Academy of Natural Sciences, Philadelphia, who searched for possible 



87 



records that would establish the issue-dates of the Transactions of the American En- 
tomological Society for 1886, and for correspondence between Wright and Horn (of 
which none seems to remain), as well as Mr. Donald Azuma, at the same institution, 
who searched for additional fragments of Dinapate upon which Horn based his new 
genus and species. Professor R. Ruibal and Mrs. G. Gordh kindly rendered the title 
and abstract in Spanish. 

Literature Cited 



Bailey, L. H. 1961. Palmaceae. In C. L. Lundell. 
Flora of Texas 3:197-199 (issued 1944). Texas 
Research Foundation, Rennev. 

Baker, N. W. 1971. Observations on the biology 
of the giant palm-boring beetle, Dinapate 
wrighti [sic] Horn. (Coleoptera: Bostrichidae). 
Journal of the New York Entomological So- 
ciety 79:31-42. 

Fisher, W. S. 1 950. A revision of the North Amer- 
ican species of beetles belonging to the family 
Bostrichidae. U.S. Department Agriculture 
Miscellaneous Publications 698. 

Henshaw, S. 1895. Third supplement to the list 
of Coleoptera of America, North of Mexico. 
American Entomological Society, Philadel- 
phia. 

Horn, G. H. 1885. (Proceedings, Month. Mtg. 
Entomol. Sect. Acad. Nat. Sci., Philadelphia, 
Dec. 14, 1885.) Transactions American En- 
tomological Society 12:xxiv. 

. 1886a. Dinapate wrightii and its larva. 

Transactions of the American Entomological 
Society (Philadelphia) 13:1-4. 

1886Zj. (Proceedings, Month. Mtg. Ento- 



mol. Sect. Acad. Nat. Sci., Philadelphia, Sep. 
23, 1 886.) Transactions American Entomolog- 
ical Society, Philadelphia 13:xix. 
Lepesme, P. 1947. Les insectes des palmiers. 
Lechevalier, Paris. 



Lesne, P. 1898. Revision des coleopteres de la 
famille des bostrychides. 3' Memoire. Annales 
Societe Entomologique France 67:438-621. 

. 1910. Revision des coleopteres de la fa- 
mille des bostrychides. 6*" Memoire: Dinapa- 
tinae et Apatinae. Annales Societe Entomo- 
logique France (1909) 78:471-574. 

. 1911. Le regime alimentaire des bostry- 
chides. Bulletin Societe Entomologique France 
16:135-138. 

. 1924. Les coleopteres bostrychides de 

TAfrique tropicale Franfaise. Encyclopedie 
Entomologique 3. Lechevalier, Paris. 

. 1938. Coleopterorum Catalogus. Pars 1 6 1 . 



Bostrychidae. W. Junk, s'-Gravenhage. 

Michelbacher, A. E., and E. Ross. 1 939. The giant 
palm borer (Coleoptera: Bostrichidae), an eco- 
nomic pest in lower California. California State 
Department of Agriculture Bulletin 28:166- 
169. 

Schwarz, E. A. 1899. (Proceedings, Mtg Dec. 2, 
1897.) Proceedings of the Entomological So- 
ciety of Washington 4:230. 

Smithe, F. B. 1974-1981. Naturalist's Color 
Guide, Part 1(1975); Color Guide Supplement, 
Part 11 (1974); Supplement, Part 111 (1981). 
American Museum of Natural History, N.Y. 



ivy 




TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 



Volume 21 Number 6 pp. 89-110 5 December 1986 

Holocene terrestrial gastropod faunas from Isla Santa Cruz and Isla 
Floreana, Galapagos: evidence for late Holocene declines 

Steven M. Chambers '-^Sf^/\p^ 

Office of Endangered Species, U.S. Fish and Wildlife Service, Washington, D.C. 20240 USA and 
Department of Biology, George Mason University, Fairfax, Virginia 22030 USA i _ 

-'^ 7986 

David W. Steadman' 

Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, 
Washington, D.C. 20560 USA ^N: 

Abstract. We report 1 6 species of land snails from late Holocene cave deposits and nearby surface 
areas on Isla Santa Cruz and Isla Roreana, Galapagos Islands. These snails are associated with vertebrate 
fossils that accumulated in lava tubes or fissures largely as the regurgitated items of bam owls (Tyto 
punctatissima). Most or possibly all of the snails, however, probably do not represent prey remains, 
but entered the cave mainly with infilling sediment. The fossil snails represent a much less complete 
sample of each island's historic fauna than do the vertebrate fossils from the same deposits. Radiocarbon 
ages on these faunas range from 2420 ± 25 years BP to Modem. Lectotypes and paralectotypes are 
designated for Naesiotus nesioticus and Naesiotus reibischi. Naesiotus galapaganus, which is rare in 
historic collections, occurred abundantly in the fossil deposits on Floreana. Five species from these 
collections on Santa Cruz had not been previously reported from this island (Gastrocopta duncana, 
Succinea corbis, Guppya bauri, and two species of Naesiotus that have recently been described else- 
where). As with vertebrates, certain species of snails have suffered considerable late Holocene declines 
in range and abundance, and possibly have become extinct in Galapagos. The causes of gastropod 
declines are not clear, but are likely related to human impact of the past century. The most likely cause 
is habitat destruction by introduced goats, donkeys, and pigs, although predation by introduced rodents 
may also be important. 

Introduction 

Fossils have traditionally played a minor role in studies of the evolution and 
biogeography in the Galapagos Islands. This is largely because few scientists have looked 
for them and have regarded the volcanic terrain of Galapagos (Fig. 1 ) to be a poor 
environment for the deposition and preservation of fossils. Invertebrate fossils have 
been reported from localized marine sedimentary rocks in Galapagos (Hertlein 1972 
and references therein), but these studies were based upon field work done decades 
before absolute dating of volcanic rocks was possible through potassium-argon and 
paleomagnetic determinations. Renewed interest in the Quaternary marine fossils of 
Galapagos (James 1984, Hickman and Lipps 1985) has resulted from new collections 
from deposits stratigraphically related to lava flows whose ages are fairly well known. 

Until the past several years, the paleontology of terrestrial organisms in Galapagos 
had received even less attention than that of marine organisms. Again, much of this 
lack of attention was due to the axiom of geology that states the rarity or lack of fossils 
in volcanic rocks. Biologists (e.g.. Lack 1960) lamented that Galapagos was, unfortu- 
nately, an area that had yielded no paleontological clues about the history of the birds 



' Present address: Biological Survey, New York State Museum, The State Education Department, Albany, 
New York 12230 USA. 



90 



91«00 



01 •00' 



00*00 — 



01*00 



.CULPEPPER 



•WENMAN 



Ci' 



PINTA 



90*00 



50 100 KM 
I I I I I I I I I I I 



30 60 MILES 
I I I I I I I 



o 



MARCHENA 



Q 



GENOVESA 



SANTIAGO 



SEYMOUR NORTE 




FERNANOINA 



SAN CRISTOBAL 




FLOREANA / y 



ESPANO 



NOLA'^~^ 



00*00 



01*00 



91*00 



90*00 



Figure 1 . Galapagos Islands, Ecuador. Dots indicate the approximate locations of the fossil sites on Floreana 
and Santa Cruz. 



or other terrestrial organisms for which these islands are so well known. This situation 
has now changed. 

In 1978 and 1980, DWS collected large samples of fossil vertebrates from Isla 
Santa Cruz and Isla Floreana (Fig. 1), and a smaller sample from Isabela. In 1984, 
large collections were made on San Cristobal, Rabida, and Isabela. Only the collections 
from Santa Cruz and Floreana yielded large samples of gastropods. The fossil vertebrates 
from Santa Cruz and Floreana, and to some extent those from Isabela, have been 
reported (Steadman 1981, 1982, 1985, 1986; Steadman and Ray 1982); from these 
reports we have abstracted the stratigraphic and chronological context of the fossil snail 
faunas, supplemented for Santa Cruz by data previously unpublished. Although none 
of the fossil deposits has been shown to pre-date even the Holocene, the paleofaunas 
nevertheless shed new light on the natural (=before human contact) distributions of 
species, and have helped to resolve problems in the systematics of living or recently 
extinct species. 

Late Holocene vertebrate paleofaunas have shown that human-caused predation 
and habitat degradation have altered natural patterns of distribution and diversity on 
islands (Pregill and Olson 1981, Olson and James 1 982^, b, Olson and Hilgartner 1 982, 
Steadman et al. 1984). In Galapagos as well, analyses of vertebrate paleofaunas have 
revealed much extinction that is related to human impact (Steadman and Ray 1982, 
Steadman 1986). The present analysis of gastropods from the same fossil sites 
provides a comparison from an entirely different element of the Galapagos paleofauna. 



91 

Site Descriptions and Sampling Methods 

The fossil snail collections are mainly from lava tubes or fissures in the arid 
lowlands. Lava tubes are especially effective repositories for terrestrial sedimentation 
in Galapagos. 

Floreana. —The fossil fauna of Floreana was collected from four caves in the Post 
Office Bay region in the north-central coast of the island (see figs. 2-3 of Steadman 
1986). The elevations of the caves range from 20 to 50 m above modem sea level. No 
cave is more than 500 m from the present seashore. Access to each cave is through a 
vertical collapse in the roof created by weathering processes such as pedogenesis, growth 
of tree roots, and percolation of water. Two of the caves, Cueva de Post Office (Inferior) 
and Cueva de Post Office (Superior), had been mapped previously by Montoriol-Pous 
and Escola (1975), who also described various physical and chemical features of the 
caves. The other two caves, Finch Cave and Bam Owl Cave, had not been mapped or 
described before our explorations. Fossils were collected from the surface of the floor 
of each cave, and except in Finch Cave, sediments were also excavated using standard 
techniques and washed through screens of V^ inch and '/k, inch mesh. The species 
composition of the faunas from excavations did not differ from that of the floor's 
surface, although, as one would expect, a higher percentage of small species (both of 
mollusks and vertebrates) was recovered from the screened sediments. Fossils were 
typically most common near the roof collapse. The sediments from all excavations 
were generally similar to each other in physical characteristics, consisting of combi- 
nations of clays, silts, sands, and gravels that were usually poorly sorted and rather 
angular. Water and gravity sliding seem to have deposited the sediments, but the poor 
sorting, poor rounding, and lack of laminations suggest a short distance of transport. 

The 20 000 vertebrate fossils from Floreana consist of nearly every resident species 
of bird, reptile, and mammal, including six species that no longer occur on Floreana: 
Geochelone elephantopus (tortoise), Alsophis biserialis (snake), Tyto punctatissima (bam 
owl), Mimus trifasciatus (Floreana mockingbird), Geospiza nebulosa (sharp-beaked 
ground-finch), and G. magnirostris (large ground-finch). The above species, except Tyto 
punctatissima, are known on Floreana from early 1 9th century specimens. The loss of 
each of these species can be related to human activities, especially the settlement of 
the island in 1832 by several hundred people (Steadman 1986). 

Six radiocarbon ages from the Floreana sites (table 2 of Steadman 1986) range 
from 2420 ± 25 years BP to Modem. Each determination is based upon material from 
the surface of the floor, as no organic material other than bone and gastropod shells 
was recovered from the sub-surface. The radiocarbon data indicate that organic material 
has been accumulating in the Floreana caves for at least the past several thousand 
years. We cannot say how much older certain of the underlying sediments are, but 
based upon similarities in faunal composition and in preservation of the bone itself, 
all excavated materials are probably also late Holocene in age. 

Santa Cruz.—Ks with the paleofaunas of Floreana, the fossil vertebrate faunas 
from Santa Cruz are derived mainly from regurgitated prey remains of bam owls {Tyto 
punctatissima), and represent a thorough sampling of the vertebrate life of the island 
before human disruption (Steadman 1986). Fossils were collected from two sites in the 
arid lowlands of southem Santa Cruz {see fig. 2 of Steadman and Ray 1982). The 
first is Cueva de Iguana, a fissure ca. 10m deep that trends east-west for at least several 
hundred meters, parallel to and seaward from the conspicuous fault scarp 400 m north 
of the Charles Darwin Research Station. The elevation of Cueva de Iguana is only ca. 
10 m, and brackish water flows through its bottom. Vertebrate fossils have accumulated 
in Cueva de Iguana in thin, unstratified pockets of sediment perched on small, horizontal 
ledges of the roughly vertical walls. Eight such accumulations included land snails. 

The second fossil site on Santa Cruz is Cueva de Kubler, a large lava tube 1.5 km 
north of Puerto Ayora, at ca. 75 m elevation. Cueva de Kubler has been mapped and 
described by Stoops (1967), Balasz (1972), and Montoriol-Pous and de Mier (1977), 
none of whom, however, noted the abundance of fossils within the cave. Five exca- 



92 

vations were made in the loose, powdery, unstratified sediments of Cueva de Kubler, 
and fossils were collected from the floor's surface as well. Excavations IIB, IIC, IID, 
and HE were in sediments that had been redeposited within the cave. Excavation IIA, 
whose sediments were the source of those in Exs. IIB-IIE, had not been redeposited. 
Therefore, unlike in Exs. IIB-IIE, the sediments of Ex. IIA contained fossils only of 
native fauna, uncontaminated by the remains of two murine rodents {Rattus rattus and 
Mus musculus) introduced onto Santa Cruz in historic times. Bones of the introduced 
rodents occurred on the surface of Ex. IIA, but not within the sediments. Excavation 
IIA (1.0 m X 3.0 m x 0.8 m deep) was spectacularly fossiliferous, especially in the 
upper half, whereas Exs. IIB-IIE, which were smaller in volume than Ex. IIA, were 
very fossiliferous throughout. A very crude estimate of the number of vertebrate fossils 
from these excavations is several hundred thousands. The sediments of both Cueva de 
Iguana and Cueva de Kubler are rather poorly sorted silts, clays, and pebbles. Deposition 
was probably through a combination of water, wind, and gravity sliding. 

The vertebrate faunas of Cueva de Iguana and Cueva de Kubler are similar, both 
being dominated by an extinct rice rat {Nesoryzomys indefessus). Two other extinct 
rodents occur in fair numbers (the smaller rice rat A'^. darwini and the giant thoma- 
somyine rat Megaoryzomys curioi). Both species of Nesoryzomys became extinct on 
Santa Cruz in the 20th century, whereas Megaoryzomys has never been recorded his- 
torically. Each species of terrestrial reptile ever reported from Santa Cruz, including 
the historically extinct land iguana {Conolophus subcristatus), occurs in the sites, as 
does nearly every species of resident bird. 

No radiocarbon ages have been determined for the paleofauna of Cueva de Iguana, 
but these fossils are undoubtedly late Holocene in age, based upon the loose nature of 
the sediments and the low level of mineralization of the fossils, some of which are 
entirely modem in appearance. Several radiocarbon ages have been determined for the 
Cueva de Kubler paleofauna, but these samples (wood) were badly contaminated with 
modem radioactive carbon, probably from surface testing of nuclear weapons in the 
Pacific (R. Stuckenrath in litt.). Unfortunately, therefore, the ages for the Cueva de 
Kubler samples vary from 1755 ± 335 years BP to 1 17.5% of Modem. Even the older 
date probably is contaminated by bomb-produced radiocarbon. Because bones and 
snails may be less prone to radioactive contamination than plant material, there is still 
hope of obtaining future determinations that have minimal contamination. Resolution 
of the chronology of Cueva de Kubler and Cueva de Iguana will depend either upon 
species-specific radiocarbon dating of bone itself, using tandem accelerator mass spec- 
trometry (such as done recently for plants by Betancourt et al. 1984), or the dating of 
large quantities of land snails through fairly standard counting techniques, as outlined 
by Goodfriend and Hood (1983) and Goodfriend and Stipp (1983). 

A surface sample of empty snail shells was collected for camparison with the cave 
samples along the trail to Tortuga Bay on Santa Cmz, ca. 1.5 km south of Cueva de 
Kubler at ca. 30 m elevation. This locality represents shells that were lying beneath 
and between large basaltic boulders along the trail. 

Systematics 

The Galapagos land snail fauna was reviewed by Dall (1 896) and Dall and Ochsner 
(1928). Additional contributions include those of Pilsbry (1897-1898, 1916-1918, 
1927-1935), Odhner (1950), A. G. Smith (1966, 1971, 1972, 1974), and Vagvolgyi 
(1974, 1977). Breure and Coppois (1978) analyzed shell and anatomical features 
of most of the Galapagos bulimulid species and rejected the subgeneric classification 
of Dall (1920). These authors also reported on the locations of type material of many 
Galapagos species and designated lectotypes for some. Breure (1979) gave additional 
information on the locations of type material in his review of the Bulimulinae. Coppois 
and Glowacki (1983) used factor analysis to study shell variation among species from 
Isla Santa Cruz. 

This report is based on over 1 000 fossil shells, which have been deposited in the 



93 




Figure 2. Shells of some Galapagos land snails. All except F and I are fossil shells from Isla Santa Cruz 
or Isla Floreana. A, Succinea corbis (USNM 861456) from Cueva de Kubler, Santa Cruz; B, Naesiotus 
galapaganus (USNM 861559) from Bam Owl Cave, Floreana; C, Naesiotus cymatias (USNM 86 1 490) from 
Cueva de Iguana, Santa Cruz; D, Naesiotus blombergi (USNM 86 1 505) from Cueva de Kubler; E, Naesiotus 
ochsneri (USNM 86 1 502) from Cueva de Kubler; F, Naesiotus reibischi lectotype; G-H, A', reibischi (USNM 
86 1532) from entrance to Cueva de Kubler; I, Naesiotus nesioticus lectotype; J-K, Naesiotus nesioticus from 
Cueva de Kubler (USNM 86 1 509); L, Naesiotus kublerensis holotype from Cueva de Kubler (USNM 842298). 
Scale bar is 10 mm. 



Division of Mollusks, National Museum of Natural History, Smithsonian Institution, 
Washington, D.C. Species were identified mainly by examination of the published 
literature and by comparison with the collections of Galapagos gastropods in the Di- 
vision of Mollusks of the National Museum of Natural History, Washington, D.C. 



94 

(specimen catalog numbers indicated by the prefix USNM); the California Academy 
of Sciences in San Francisco (CAS); the Academy of Natural Sciences of Philadelphia 
(ANSP); and the Museum of Comparative Zoology of Harvard University (MCZ). Type 
material was examined for all but three of the species identified from fossils. No attempt 
was made to revise classification at the generic or familial levels. 

Unfortunately, no detailed, comprehensive account has been published on the land 
snails collected in 1964 during the Galapagos International Scientific Project, now 
housed mainly at the California Academy of Sciences. A. G. Smith (1966) provided 
an informative summary, but these collections have not yet been described in detail. 
A thorough review of this collection and associated field notes would improve our 
understanding of the habitats occupied by the various species of land snails. The habitat 
data available in Ochsner's (1905-1906) field notes, R. P. Smith's (1971) unpubHshed 
study, and Coppois' (1984) transect study of the northern slope of Santa Cruz are useful 
but are inadequate to make definitive statements about the range of habitats of land 
snails, thus limiting our interpretations of the fossil fauna. 

Class Gastropoda Cuvier, 1797 
Subclass Prosobranchia Milne Edwards, 1848 (=Streptoneura Spengel, 1881) 

Order Archaeogastropoda Thiele, 1925 

Family Helicinidae Latreille, 1825 

Genus Helicina Lamarck, 1799 

Helicina nesiotica Dall, 1892 

Helicina (Idesa) nesiotica DALL, 1892, p. 97. 
Sturanva nesiotica (Dall). WAGNER 1905-191 1, p. 45. 
Helicina nesiotica Dall. A. G. SMITH 1971, p. 7. 

Typ^.-Holotype: USNM 107324. PI. XV, figs. 1-2, in Dall (1896). Type locality 
is Chatham (San Cristobal) Island at 1600 feet (488 m) above sea level (Dall 1892). 

Material. -U^'NM 861375-861395 (Santa Cruz), USNM 861396 (Floreana). 

Remarks. —Two species oi Helicina have been described from Galapagos, both by 
Dall (1892, 1917). Helicina nesiotica is based on a specimen from Isla San Cristobal 
(Chatham). Dall's descriptions (1892, 1896) of this species refer to its "bright reddish 
chestnut epidermis" or periostracum. Dall described Helicina ochsneri Dall, 1917 from 
material (type: USNM 2 1 602 1) from Isla Isabela (Albemarle). He described this species' 
periostracum as "blackish," but noted that removal of the periostracum of//, ochsneri 
exposed a shell with a surface and color similar to //. nesiotica. 

All the fossil Helicina lack the periostracum, so their identification as //. nesiotica 
is based on the sizes of the fossil specimens. Shell height/diameter for //. nesiotica is 
3.3 mm/2.3 mm (Dall 1892) and for //. ochsneri is 4.7 mm/3.5 mm (Dall 1917). Some 
fossil individuals approach the measurements stated for //. ochsneri and may belong 
to that species. 

Dall and Ochsner (1928) reported H. nesiotica from Roreana. Based on exami- 
nation of CAS material and the holotype, the Helicina reported from Santa Cruz by 
A. G. Smith (1966) is //. nesiotica. 

Subclass Pulmonata Cuvier, 1817 (=Euthyneura Spengel, 1881, in part) 

Order Stylommatophora A. Schmidt, 1856 

Family Achatinellidae Gulick, 1873 

Subfamily Tomatellininae Pilsbry, 1910 

Genus Tornatellides Pilsbry, 1910 
Tornatellides chathamensis (Dall, 1892) 

Leptinaria chathamensis DALL, 1892, p. 98. 
Tornatellina chathamensis (Dall). DALL 1900, p. 95. 
Tornatellides chathamensis (Dall). ODHNER 1950, p. 254. 

Types. -\J%'\<iM 107322 (6 syntypes). One specimen in PI. XVI, fig. 9, of Dall 



95 

(1896). Type material was taken on ferns at 1600-2000 feet (488-610 m) above sea 
level on Chatham (San Cristobal) Island. 

Material. -VSNM 861397-861403 (Santa Cruz). 

Remarks. —Placement of this species in Tornatellides and the subfamily Toma- 
tellininae of the family Achatinellidae follows Cooke and Kondo (1960). Vagvolgyi 
(1974) noted that Tornatellides chathamensis and Nesopupa galapaganus Vagvolgyi, 
1974 represent the only Indo-Pacific elements in the Galapagos land snail fauna, which 
is otherwise Neotropical in origin. 

Cooke and Kondo (1960:246) observed that individuals in two lots in the Bishop 
Museum (BPBM 115299 from Chatham [San Cristobal] Island and BPBM 115300 
from Albemarle [Isabela] Island) are not as sharply conical as the specimen figured by 
Dall ( 1 896, PI. 1 6, fig. 9). SMC compared the fossil specimens with the syntypes (USNM 
107322), finding that the fossils likewise are less conical than the figure and syntypes. 

Dall (1896) included Bulimulus (Pelecostoma) cymatoferus Reibisch, 1892 in his 
synonymy for this species. Dall's name was published earlier in 1892 and therefore 
has priority. Our examination of Reibisch's (1892) description and figure suggest that 
Dall's assessment was correct, although we have not seen Reibisch's type material (see 
comments below on types of Gastrocopta clausa). 

Smith (1966) first reported Tornatellides from Santa Cruz. 

Family Pupillidae Turton, 1831 

Genus Gastrocopta WoUaston, 1898 

Gastrocopta duncana Pilsbry, 1931 

Gastrocopta duncana PILSBRY, 1931, p. 65-66, PI. 17, figs. 1-2. 

Types.— M^^V 152689 includes the lectotype designated by Baker (1963) and 3 
paralectotypes. Additional paralectotypes: ANSP 152690 (8 shells) and ANSP 152691 
(5 shells). Pilsbry (1931) reported that the 17 specimens of the type m.aterial were 
collected with Gastrocopta clausa on the south side of Duncan (Pinzon) Island. He 
stated that these localities were from 500 feet (152 m) elevation to the summit (457 
m), with G. duncana being more abundant at the summit. 

Material. -US'HM 861404 (Santa Cruz). 

Remarks.—^ single specimen from the trail near Cueva de Kubler, Santa Cruz, 
represents the first record of this species outside of Isia Pinzon. 

Gastrocopta clausa (Reibisch, 1892) 

Pupa (Leucochila) clausa REIBISCH, 1892, p. 15. 
Gastrocopta clausa (Reibisch). PILSBRY 1916, p. 99. 

Types.— The location of Reibisch's type material for this species is not known to 
us, although Breure (1979) reported that some of Reibisch's bulimulid type material 
is in the British Museum (Natural History) and the Zoologisches Museum der Hum- 
boldt-Universitat in Berlin. Reibisch's (1892) description includes a figure (PI. II, fig. 
10) and a description of the type locality as shrubs near the sea. Indefatigable (Santa 
Cruz) Island. 

Material. -VSNM 861405-861426 (Santa Cruz), USNM 861427-861440 (Flo- 
reana). 

Remarks. —Pilshry (1931:69) considered Gastrocopta clausa to be very similar to 
but distinct from Gastrocopta munita (Reibisch, 1892), the former having a well de- 
veloped subcolumellar tooth that is either absent in G. munita or very weakly tuber- 
culate, consisting only of a sloping callus. Later, Pilsbry (1931:71 and pi. 17) referred 
to specimens of G. clausa from Chatham (San Cristobal) Island that lacked this sub- 
columellar tooth. These observations plus LaRochelle's (1983) report of apparent in- 
traspecific variation in tooth number among some North American pupillids lead us 
to question the reliability of this character for separating these two species. The other 
character that Pilsbry used to separate these species, the presence of a nodule associated 



96 

with the parietal lamella that is present in his "typical" G. clausa, but absent in G. 
munita, also seems deficient as a diagnostic character. The fossils are identified as G. 
clausa because of the presence of a subcolumellar lamella, expressed to varying extents, 
and the lack of any other apparent and consistent variation among them. A revision 
of the Galapagos Gastwcopta, a preliminary version of which was very briefly described 
in an abstract by Vagvolgyi (1979), could resolve some of the confusion concerning 
these forms. 

Family Succineidae Beck, 1837 

Genus Succinea Drapamaud, 1801 

Succinea corbis Dall, 1893 

Figure 2A 

Succinea corbis DALL, 1893, p. 55. 

7>j^£'5.-USNM 107321 (13 syntypes). PI. XV, fig. 5, of Dall (1896). The type 
locality is Albemarle (Isabela) Island. 

Material. -US^M 861441-861465 (Santa Cruz). 

Remarks. —Species identifications based on shell material alone must be considered 
tentative in this difficult family. The fossil Succinea are referred to S. corbis because 
they possess the fine microsculpture that Dall (1893) described as "an excessively fine 
network of closely reticulated fine incised lines." Dall and Ochsner (1928) later stated 
that the "lattice-like corrugation" had disappeared from the type material owing to 
contraction of the periostracum. SMC has examined the syntypes and found this mi- 
crosculpture to be seen easily under 30 x magnification. 

Expression of the fine microsculpture ranges from strong to faint. The fine micro- 
sculpture was not visible on some of the smaller or more eroded shells. These were 
identified as S. corbis because they differed in no other way from the microsculptured 
shells in the same lots, although it cannot be ruled out that some or all of these are 
Succinea bettii Edgar Smith, 1877. The specimen (USNM 107318) that Dall (1896, PI. 
XV, fig. 6) apparently portrayed as an example of S. bettii shows the S. corZjz^-like 
microsculpture on unworn outer surfaces of the shell and is considered here to be S. 
corbis. We have not examined the type material of S. bettii; it is probably in the British 
Museum (Natural History) [BM(NH)], where Edgar Smith was keeper of mollusks. 
Examination of this material for microsculptural features would aid in determining 
whether S. bettii and S. corbis are synonyms. 

A similar pattern of microsculpture is present in two shells (USNM 163056 and 
USNM 216030) from Cocos Island, Costa Rica, although the overall shell form of 
these individuals is very short-spired and therefore distinct from S. corbis. Another 
example may be that referred to as "crisscross" sculpture by Solem (1959) in his 
discussion of Quick's (1939, 1951) work on some Austromalayan Succinea. 

This is the first record for Succinea corbis on Santa Cruz. 

Family Bulimulidae Tryon, 1867 
Genus Naesiotus Albers, 1850 

Remarks.— Tho, full generic status of Naesiotus, including the Galapagos species, 
has been recognized by A. G. Smith (1971, 1972, 1974), Vagvolgyi (1977), Breure and 
Coppois (1978), and Breure (1979), although Coppois and Glowacki (1983) recognized 
Naesiotus as a subgenus of Bulimulus. 

Naesiotus galapaganus (Pfeiffer, 1854) 
Figure 2B 

Bulimus galapaganus PFEIFFER, 1854, p. 58. 

Bulimulus (Naesiotus) galapaganus (PfeifTer). DALL 1896, p. 435 [synonymy]. 

Naesiotus galapaganus (Pfeiffer). BREURE AND COPPOIS 1978, p. 176. 

rj/7^5. -Lectotype [BM(NH) 1975 146] and paralectotype [BM(NH) 1975 147] des- 
ignated by Breure and Coppois (1978) (not seen). Pfeiffer (1854) listed the type locality 
only as the "Galapagos Islands." 



97 



Table 1 . Measurements of shells of some adult Naesiotus. Ranges are within parentheses. Specimens are 
from Santa Cruz unless otherwise indicated. 





Sample 


Shell height 


Terminal apical 


Specimens 


size 


in mm 


angle in degrees 


Naesiotus nesioticus: 








Lectotype 


1 


13.2 


26 


Paralectotypes 


3 


12.8 


26.7 






(11.6-14.7) 


(22-31) 


USNM 215982 


5 


13.0 


24 






(11.6-13.7) 


(22-26) 


Trail to Tortuga Bay 


4 


12.6 


23.8 






(11.6-13.1) 


(22-26) 


Cueva de Kubler surface 


2 


12.6 


21.5 






(12.3-12.8) 


(20-23) 


Cueva de Kubler Excavation IIA 


24 


13.2 


23.3 






(12.3-17.3) 


(20-27) 


Cueva de Kubler Excavation IIB 


9 


12.9 


23.1 






(11.5-14.0) 


(18-26) 


Cueva de Kubler Excavation IIC 


4 


13.2 


23 






(12.8-13.5) 


(22-44) 


For all N. nesioticus above 


52 


13.0 


23.5 






(11.5-17.3) 


(18-31) 


Naesiotus reibischi: 








Lectotype 


1 


10.9 


15 


Paralectotype 


1 


9.6 


17 


USNM 534106 (James Island) 


3 


11.4 


15.3 






(10.9-11.9) 


(15-16) 


Cueva de Iguana 


12 


11.8 


16.2 






(10.9-13.1) 


(14-17) 


Cueva de Kubler surface 


18 


11.8 


16.2 






(10.5-13.3) 


(13-18) 


Cueva de Kubler Excavation IIA 


2 


12.4 


17.5 






(12.2-12.6) 


(17-18) 


For all A^. reibischi above 


37 


11.7 


16.2 






(9.6-13.3) 


(13-18) 


Naesiotus kublerensis: 








Holotype 


1 


10.9 


36 


Paratypes: 








Cueva de Kubler surface 


24 


11.0 


34.3 






(10.1-12.2) 


(30-40) 


Cueva de Kubler Excavation IIA 


1 


11.4 


29 


Naesiotus duncanus holotype 


1 


18.9 


50 


Naesiotus hirsutus holotype 


1 


9.9 


44 


Naesiotus cavagnaroi MCZ paratypes 


6 


21.6 


56 






(19.8-23.2) 


(51-62) 



Material. -USNM 861551-861613 (Roreana). 

Remarks.— Wq are not aware of any published records of this species since Dall 
(1896) reported it among the collections made by G. Baur in 1890. This species was 
found in large numbers in all fossil deposits sampled on Floreana. 

Naesiotus cymatias (Dall, 1917) 
Figure 2C 

Bulimulus (Naesiotus) cymatias DALL, 1917, p. 380. 
Naesiotus cymatias (Dall). BREURE 1979, p. 69. 

Type. -CAS 1667 (not seen). Photograph in Dall and Ochsner (1928: fig. 19). The 
type locality is described by Dall (1917) as "Indefatigable [Santa Cruz] Island, under 
lava blocks in a moist area between 400 and 600 feet [122 and 183 m] elevation." 

Material. -VSNM 861474-861498 (Santa Cruz). 



98 



Naesiotus ochsneri (Dall, 1917) 
Figure 2E 

Bulimulus (Naesiotus) ochsneri DALL, 1917, p. 38. 
Naesiotus ochsneri (Dall). A. G. SMITH 1972, p. 12. 

7-y;,^5._Holotype: CAS 1668; fig. 20 in Dall and Ochsner (1928). Paratypes: CAS 
1490 (3 shells); CAS 1669 and 1670 (one shell each) are labeled as "syntypes"; USNM 
215932 (ten shells) labeled as paratypes and with collection data identical to that 
accompanying Dall's description. The type locality is described as "Indefatigable Island, 
under lava blocks at 200 to 650 feet [61 to 198 m]" (Dall 1917). 

Material. -VSNM 861449-861504 (Santa Cruz). 

Naesiotus nesioticus (Dall, 1896) 
Figure 2I-K 

Bulimulus (Naesiotus) nesioticus DALL, 1896, p. 443. 
Bulimulus (Naesiotus) naesioticus [sic] Dall, DALL 1920, p. 121. 
Naesiotus nesioticus (Dall). BREURE 1979, p. 70. 

Types.— US'NM 107277 (Fig. 21) is here designated the lectotype. This specimen 
was figured by Dall (1896, PI. XVI, fig. 1) with the original description. A printed label 
with the specimen indicates that it is the figured "type." The protoconch is mostly 
missing. Measurements of the four specimens of USNM 107277a, here designated 
paralectotypes, are presented in Table 1 . The type locality is James Island (Isla Santiago). 

Material. -US^M 861506-861529 (Santa Cruz). 

Remarks.— This species is further discussed below with Naesiotus kublerensis. 



Naesiotus reibischi (Dall, 1895) 
Figure 2F-H 

Bulimulus (Naesiotus) Reibischii DALL, 1895, p. 26. 

Bulimulus (Naesiotus) Reibischi Dall. DALL 1896, p. 444 [emendation]. 

Naesiotus reibischi (Dall). BREURE AND COPPOIS 1978, p. 183. 

Types. -The shell (USNM 107279) depicted in PI. XVI, fig. 4, of Dall (1896) and 
Figure 2F of this paper is here designated the lectotype. This specimen's label indicates 
that it is the figured "type." USNM 107279a, apparently the second specimen men- 
tioned by Dall (1895:127) in the type lot, is here designated a paralectotype. Some 
measurements of these specimens are presented in Table 1 . The type locality is Inde- 
fatigable Island (Isla Santa Cruz). 

Material. -VSNM 861530-861550 (Santa Cruz). 

Remarks.— The long, slender fossil bulimulids are identified here as either A^. 
nesioticus or A^. reibischi (Fig. 2F-K). Coppois and Glowacki (1983) reported two 
additional slender species, which they referred to as unidentified, from Santa Cruz (see 
remarlcs on Naesiotus kublerensis). Another long, slender species, Naesiotus rugiferus 
(Sowerby, 1833), has been reported from Santa Cruz by R. P. Smith (1971) and Breure 
and Coppois (1978). Coppois and Glowacki described the apical sculpture of their two 
unidentified species and A^. nesioticus as undulating riblets. Breure and Coppois (1978) 
described the protoconchal sculpture of A^. rugiferus as undulating and A^. reibischi as 
straight. Examination of the protoconchs of our material and the USNM types revealed 
that the riblets are straight in the type material of both A^. reibischi and A^. nesioticus. 
This feature could not be discerned reliably in most of our fossil material; the riblets 
were mostly straight when visible, with some waviness in a few individuals, especially 
material here referred to N. reibischi. The slight variation observed in this feature in 
the fossil shells provides no basis for referring them to species other than A^. reibischi 
and N. nesioticus. Naesiotus reibischi is further discussed in the comments below on 
Naesiotus kublerensis. 



99 



Naesiotus blombergi (Odhner, 1950) 
Figure 2D 

Bulimulus blombergi ODHNER, 1950, p. 255. 

Naesiotus deroyi A. G. SMITH, 1972, p. 9. 

Naesiotus blombergi (Odhner). A. G. SMITH 1974, p. 67. 

7>/7^5.— Breure (1979:68) indicated that a holotype was in the Swedish State Mu- 
seum of Natural History (Naturhistoriska Riksmuseet) in Stockholm. We are not aware 
of any published designation of a lectotype for this species. In the original description, 
Odhner (1950) indicated that 12 specimens constituted the type material and described 
the type locality as being ''200-300 m above sea level on plants, bushes, and trees" on 
Isla Santa Cruz. That description included figures (Figs. 1, 3-5) of an apertural view 
of the shell of a single specimen and of apical sculpture, jaw, and radula. 

A. G. Smith (1972) designated CAS 13730 as the holotype of TV. deroyi. He also 
designated 72 paratypes, which he indicated that he had distributed to various museums 
and private collections. These paratypes include the 4 alcohol-preserved specimens of 
MCZ 280009 and 4 dry specimens of USNM 735981, all of which were examined in 
the present study. Smith's type material was taken on a thorny bush at 264 m elevation 
on the northwest side of Isla Santa Cruz. 

Material -\JSHM 861505 (Santa Cruz). 

Naesiotus kublerensis Chambers, 1986 
Figure 2L 

Naesiotus kublerensis CHAMBERS, 1986, p. 289. 

Types. -Uo\o\y^Q (USNM 842298) and paratypes (USNM 842299, 7 shells; USNM 
842300, 1 shell; USNM 842301, 7 shells; USNM 842302, 5 shells; USNM 842303, 
25 shells) from the entrance of or within Cueva de Kubler, Santa Cruz (Chambers 
1986). Figure 2L is of the holotype. Paratypes in figure 3 of Chambers (1986) include 
two shells from USNM 842299 and three shells from USNM 842301. 

Material. -USNM 842298-842304 (Santa Cruz). 

Remarks. —Among the several, high-spired Naesiotus species reported from Santa 
Cruz are two "unidentified" species reported by Coppois and Glowacki (1983), whose 
work represents an important quantitative comparative study of Santa Cruz bulimulids. 
Assigning names to our three elongate species of fossil Naesiotus (N. reibischi, N. 
nesioticus, and A'^. kublerensis) and comparison with the available data on Coppois and 
Glowacki's unidentified species necessitated a more detailed analysis (described below) 
using the method developed by those authors. In this analysis, the elongate species are 
compared with respect to two measurements: shell height and terminal apical angle. 
Coppois and Glowacki (1983) concluded from factor analysis of seven measurements 
that these two measurements defined intraspecific variation well enough that in most 
cases an individual bulimulid shell from Santa Cruz could be assigned to a species 
simply by taking these two measurements and comparing them to those of known 
samples of only five shells per species, as portrayed in their Figure 3. 

In the present study, these two characters were determined (to the nearest . 1 mm 
or the nearest whole degree) for shells of A^. nesioticus, N. reibischi, N. kublerensis, and 
to available type material for these and other species, following the methods of Coppois 
and Glowacki. These data are summarized in Table 1 and Figure 3. 

Three major clusters (represented by triangles, circles, and squares, respectively) 
of points are discemable in Figure 3. The most discrete of these consists of shells here 
considered as representing A^. reibischi (squares) and including the type material for 
that species. This cluster overlaps the coordinates representing Coppois and Glowacki's 
unidentified species "22" and "56" and is disjunct from their values for A^. reibischi. 
In the absence of further information on species "22" and "56," and based on the 
coordinates of the type material, we refer these very slender shells to A^. reibischi. 

The cluster representing our material of A^. nesioticus (circles) overlaps Coppois 



100 



45 



40 



O 

Z 

< 



< 



35 



30 



^25 

< 
Z 20 



15 



10- 



0- 









AA A A; 







A 


A 68 ! 

\^ 1 


A 








A 




Aa! 


A 
A 


A 
O 










V 


e 

o® 


. ^ ^A 

-^ 81 ^~~^^-i 












® 


O 00 o 
OO ® (KD OO O 
® O O 
9-0 00 (DO 


e 


- 






D 


D 


kT 7 "--. 000 

D ~~"~~--"o 





B 






■oa 


wmm 


  ^C D 




- 




r^ 




am 


56 /-^  



















10 II 12 13 14 

SHELL HEIGHT (mm) 





N. reibischi 


N. 


nesioticus 


N.k 


ubierensis N. hirsutus 


KUBLER 




D 









A 


IGUANA 




 










TRAIL 








© 






USNM 




m 




® 






LECTOTYPE 




s 




e 




HOLOTYPE 


PARALECTOTYPE 


B 




e 







Figure 3. Variation in two characters in some elongate Naesiotus. Each symbol may represent more than 
one individual. Numbered areas enclosed by dashed lines were drawn after fig. 3 of Coppois and Glowacki 
(1983) and delimit their ranges of these measurements for A", reibischi (7), A^. hirsutus (18), A^. jacobi (68), 
TV. nesioticus (81), and two unidentified species of Naesiotus (22 and 56). Shells are from Isla Santa Cruz, 
except the type and "USNM" material of A', nesioticus. 



101 

and Glowacki's coordinates for both N. reibischi and N. nesioticus. These are identified 
here as N. nesioticus because this cluster includes the lectotype of TV. nesioticus and is 
disjunct from the N. reibischi type material. Most shells in this cluster are more slender 
than the lectotype. We do not believe that this cluster represents common ancestors 
of A^. reibischi and A^. nesioticus because it includes non-fossil material. In addition, 
neither character is correlated with depth in fossil deposits. As discussed above in the 
remarks on A^. reibischi, the differences between N. reibischi and N. nesioticus in apical 
sculpture of the shell cited by Coppois and Glowacki (1983) are not supported by the 
type material. 

The third cluster (triangles) represents Naesiotus kublerensis and includes a wider 
range of values for terminal apical angle, but a narrower range for shell height, than 
the other two clusters. A lectotype of TV. nesioticus is found near the edge of this cluster, 
which also overlaps Coppois and Glowacki's (1983) coordinates for Naesiotus hirsutus 
Vagvolgyi, 1977 and Naesiotus jacobi (So-werhy, 1883). Naesiotus kublerensis, however, 
possesses axial sculpture that becomes rugose on the body whorl, which is not found 
on either A^. Jacobi or A^. hirsutus (Chambers 1986). 

The failure of some type material to fall within Coppois and Glowacki's circum- 
scribed boundaries for the corresponding species led us to measure these two characters 
in additional available Naesiotus type material. Coordinates representing the type of 
Naesiotus duncanus (Dall, 1893), the paralectotype of A^. reibischi, and some MCZ 
paratypes of Naesiotus cavagnaroi A. G. Smith, 1972, fall outside the limits circum- 
scribed for these species by Coppois and Glowacki (1983). The lectotypes of A^. nesi- 
oticus and A^. reibischi fall within the limits set by Coppois and Glowacki, but the two 
paralectotypes of A^. nesioticus fall outside. Although Coppois and Glowacki (1983: 
2 1 5-2 1 6) found that five specimens for each species adequately described the range of 
variation of larger samples for the species that they studied, their samples did not 
encompass the variation in all type material and in our material of A^. nesioticus and 
A^. reibischi. 

Naesiotus steadmani Chambers, 1986 
Naesiotus steadmani CHMA^ERS, 1986, p. 287. 

Types. -ThQ holotype (CAS 059358) and 67 paratypes (CAS 038052) are shells 
collected under lava rocks on a cliff above Academy Bay, Santa Cruz. Figure 1 of 
Chambers (1986) portrays the holotype and three paratypes. 

Material. -\JS\^M 842297 (Santa Cruz). 

Remarks.— ThQ single fossil specimen {see fig. 1 of Chambers 1986) resembles A^". 
cymatias, but has a higher spire than that species. It is more weathered in appearance 
than most of the other fossil shells. The type material was collected on Santa Cruz, but 
not identified, by A. G. Smith in 1964. 

Family Helicarionidae Godwin-Austen, 1888 

Genus Guppya Morch, 1867 

Guppya bauri (Dall, 1892) 

Zonites {Hyalinia) Baueri DALL, 1892, p. 98. 
Trochomorpha bauri (Dall). DALL 1896, p. 447 [emendation]. 
Guppya bauri (Dall). DALL 1900, p. 92. 

Typ^.-USNM 107317. PI. XV, figs. 8-9 in Dall (1896). The type, which for many 
years was the only known specimen, was found on ''South Albemarle [Isabela] Island 
on weathered bones of tortoises" (Dall 1892). 

Material. -US^M 861466-861467 (Santa Cruz). 

Remarks. —B^ktv (1941:223) suggested that this species may belong in the genus 
Habroconus Fischer and Crosse. This species has been reported from Espaiiola, Pinzon, 
Isabela, and Pinta (Dall and Ochsner 1928), but not previously from Santa Cruz. 



102 



Genus Habroconus Fischer and Crosse, 1872 
Habroconusl galapaganus (Dall, 1893) 

Conulus galapaganus DALL, 1893, p. 55. 

Euconulus galapaganus (Dall). DALL AND OCHSNER 1928, p. 175. 

Habroconusl galapaganus (Dall). A. G. SMITH 1971, p. 7. 

Types.-US^M 107315 (three syntypes), PI. XV, fig. 11 in Dall (1896). Type 
locality is described on the label of the syntypes as the southwestern end of Chatham 
Island (San Cristobal) at 1600 feet (488 m). 

Material. -VSl^M 861468 (Santa Cruz). 

Remarks.— BakQV (1941:223) commented that this species may also belong in 
Habroconus, a suggestion apparently followed by Vagvolgyi (1975, Table 4). A. G. 
Smith (1966) reported Euconulus (= Habroconus?), probably this species, from Isla 
Santa Cruz. 

Family Zonitidae Morch, 1864 

Genus Retinella Fischer in Shuttleworth, 1877 

Retinella? chathamensis (Dall, 1893) 

Hyalinia chathamensis DALL, 1893, p. 54. 
Vitrea chathamensis (Dall). DALL 1896, p. 448. 
Retinella? chathamensis (Dall). A. G. SMITH 1971, p. 7. 

Type. -USNM 107316. PI. XV, figs. 3, 10 in Dall (1896) appear to be illustrations 
of the type. Dall (1893) described the type locality as 1600 feet (488 m) on Chatham 
(San Cristobal) Island. 

Material. -IJSNM 861469-861473 (Santa Cruz). 

Remarks.— Although reported from a number of islands in Galapagos (Dall and 
Ochsner 1928), this species had not been recorded on Santa Cruz until A. G. Smith's 
1966 report. 

Discussion 

Distribution of species in fossil deposits.— Only three species were found as fossils 
at the Floreana localities (Table 2). Two of these, Helicina nesiotica and Gastrocopta 
clausa, are small species more commonly recorded from screened excavations than 
from hand-picked surface remains. Naesiotus galapaganus is extremely abundant in 



Table 2. Fossil land snails from Floreana. X indicates the presence of the species. 





Helicina 


Gastrocopta 


Naesiotus 




nesiotica 


clausa 


galapaganus 


Cueva de Post Office (Superior) 








Surface 




X 


X 


Excavation 1 






X 


Excavation 2 






X 


Excavation 3 




X 


X 


Excavation 4 






X 


Cueva de Post Office (Inferior) 








Surface 




X 


X 


Excavation 1 




X 


X 


Excavation 2 






X 


Excavation 3 






X 


Bam Owl Cave 








Surface 






X 


Excavation 


X 


X 


X 


Finch Cave 








Surface 






X 



103 



Table 3. Land snails from Cueva de Iguana, Santa Cruz. Numbers in Tables 3-6 indicate the minimum 
number of individuals represented by the fossil material. 





Site 


Site 


Site 4E 


Site 4W 


Site 5E 


Site 5W 






Area 


Area 


Ledge 


Area 


Ledge 


Site 




3 


4E 


A 


B 


1 


B 


2 


6E 


Helicina nesiotica 










1 








Tornatellides chathamensis 


















Gastrocopta duncana 


















Gastrocopta clausa 






1 




1 








Succinea cordis 


5 


2 


1 


6 


5 




1 


2 


Naesiotus cvmatias 


11 


6 


9 


14 


12 


10 


9 


28 


Naesiotus ochsneri 


















Naesiotus nesioticus 


















Naesiotus reihischi 


4 


1 


2 


4 


7 


2 


4 


7 


Naesiotus blombergi 


















Naesiotus kublerensis 


















Naesiotus steadmani 


















Guppya bauri 


















Habroconusl galapaganus 


















Retinellal chathamensis 



















all Floreana samples, although this Floreana endemic has only rarely been collected 
before. 

On Santa Cruz, Naesiotus cymatias was by far the most common species found 
in excavations. Thousands of shells of this species were recovered from the excavations 
in Cueva de Kubler and Cueva de Iguana. Tornatellides chathamensis, Succinea cordis, 
and Naesiotus reibischi were also found at all sites, but in lesser numbers. 

Only four species were recovered from Cueva de Iguana (Table 3). In contrast to 
the Kubler excavations, Naesiotus reibischi was found in Cueva de Iguana in the absence 
of A^. nesioticus. Species composition was similar for all sites within Cueva de Iguana, 
except that Helicina nesiotica was recovered only from Site 4W. 

All 14 species from excavations on Santa Cruz were found in Cueva de Kubler 
(Tables 4-6). A notable feature of the Kubler fauna is the abundance of A^. nesioticus, 
which was not found at Cueva de Iguana. The similar, high-spired species A^. reibischi 
was also present, but in smaller numbers. Samples of shells taken from the surface of 
soil deposits among boulders both just outside and within the cave entrance also 



Table 4. Land snails from entrance and Excavation IIA in Cueva de Kubler (except column under "Trail"), 
Santa Cruz. The Trail site represents a surface collection of shells from beneath boulders. 







Surface: 






Excavation IIA 








near 


Entrance 


0-20 


20-40 


40-60 


60-80 




Trail 


entrance 


rubble 


cm 


cm 


cm 


cm 


Helicina nesiotica 


3 


7 


16 


111 


1 




16 


Tornatellides chathamensis 


1 




1 


3 


3 




1 


Gastrocopta duncana 
Gastrocopta clausa 
Succinea corbis 


1 
3 

1 


38 
26 


6 

18 


48 
21 


6 


1 


1 

2 


Naesiotus cvmatias 


171 


-1000 


159 


-2200 


246 


74 


19 


Naesiotus ochsneri 
















Naesiotus nesioticus 


21 




2 


107 


1 


1 




Naesiotus reibischi 




91 


21 


6 








Naesiotus blombergi 
Naesiotus kublerensis 


1 


38 




9 








Naesiotus steadmani 
















Guppya bauri 
Habroconusl galapaganus 
Retinella? chathamensis 








1 
1 






1 



104 

Table 5. Land snails from Cueva de Kubler, Excavation IIB, Santa Cruz. 



Surface 



0-6 


6-12 


12-18 


18-24 


24-30 


30-36 


cm 


cm 


cm 


cm 


cm 


cm 



Helicina nesiotica 3 399 3 3 1 7 

Tornatellides chathamensis 

Gastrocopta duncana 

Gastrocopta clausa 4 6 2 11 

Succinea corbis 10 2 2 

Naesiotus cymatias 109 -1100 -600 433 339 403 73 

Naesiotus ochsneri 1 3 

Naesiotus nesioticus 9 70 23 17 7 10 5 

Naesiotus reibischi 4 112 4 

Naesiotus blombergi 1 



Naesiotus kublerensis 

Naesiotus steadmani 

Guppya bauri 

Habroconus? galapaganus 

Retinellal chathamensis 1 1 



contained both species, but A^. reibischi was by far the more common. This is curious 
because these samples were taken from places that would seem to be source areas for 
snail shells washed into Cueva de Kubler after severe rains. We believe, however, that 
the snails are from the immediate catchment basin and have not been transported from 
other habitats. The sample of shells from the trail to Tortuga Bay (collected from the 
surface of soil deposits among boulders, just as in the surface sample from outside 
Cueva de Kubler) contained TV. nesioticus, but not A^. reibischi. Of these two species, 
the more common one (A^. nesioticus) in the Kubler fossil sites and in the surface site 
near the trail to Tortuga Bay (downslope from Cueva de Kubler) is less common at 
and near the entrance of Cueva de Kubler. The absence of A^. nesioticus from the Cueva 
de Iguana sites may indicate vegetational preference, because Cueva de Iguana is about 
65 m lower in elevation than Cueva de Kubler, and one of us (DWS) has observed 
that the area around Cueva de Iguana lacks several species of woody plants that are 
common near Cueva de Kubler. 

Naesiotus kublerensis was found only in the surface samples from near the trail to 
Tortuga Bay and near the entrance to Kubler, and in the top level of Kubler Excavation 
IIA. It is absent from deeper levels of IIA and from other excavations in Kubler and 
the Iguana sites. 

Table 6. Land snails from Cueva de Kubler, Excavations IIC and HE, Santa Cruz. 

Excavation IIC Excavation HE 



0-6 6-12 12-18 18-24 24-30 20-30 30-40 

cm cm cm cm cm cm cm 



Helicina nesiotica 9 100 9 24 

Tornatellides chathamensis 1 

Gastrocopta duncana 

Gastrocopta clausa 

Succinea corbis 1 1 

Naesiotus cymatias 2 9 12 6 9 

Naesiotus ochsneri 1 1 

Naesiotus nesioticus 3 8 4 3 6 

Naesiotus reibischi 1 

Naesiotus blombergi 

Naesiotus kublerensis 

Naesiotus steadmani 

Guppya bauri 

Habroconusl galapaganus 

Retinellal chathamensis 



28 


53 


2 


7 


500 


-500 


9 


3 


12 


21 


1 




1 






2 




1 



105 



Twelve of the 17 shells of A^. ochsneri were found in Kubler Excavation HE. The 
five additional shells were found in Excavations IIB and IIC. Strangely, this species 
was absent from Excavation IIA, whose sediments represent the source area for the 
sediments of Excavations IIB and IIC. This is significant because only Excavation IIA 
is uncontaminated by post-European introductions. Several of these fossils consist of 
only a body whorl, lacking a shell spire. This damage pattern may indicate predation 
by rodents (Stokes 1917), and it is possible that these snails were carried into the cave 
by introduced rodents (most likely Rattus rattus) after the extinction of native rodents 
(Steadman and Ray 1982). 

Deposition of land snails in fossil sites. —The snails probably entered the caves by 
several means. 1) Land snails commonly retreat into moist areas, including crevices 
and caves, during daily or seasonal dry periods. 2) Snails or their empty shells are 
washed into the caves with sediment influx during periods of extremely high rainfall. 

3) Birds, rodents, or lizards may bring snails into caves as prey items. Most fossil shells, 
however, lacked damage patterns that might indicate such predation. An exception is 
Naesiotus ochsneri, discussed above. Snail shells were not present in owl pellets {see 
Mienis [197 1] for a report of snail shells in pellets from the owl Athene noctua in Israel). 

4) Snails entering the caves may have remained there to feed upon the accumulated 
bones and shells, which represent a rich source of calcium. 

If some species of snails tend to feed on bones and shells more than others, then 
factor 4 may at least partially explain why some species and not others were found in 
cave deposits. Of the 5 1 species of land snails reported from Floreana or Santa Cruz 
or both, five have been recorded in the literature as having been collected on bones 
outside of cayQS— Tornatellides chathamensis, Gastrocopta clausa, Gastrocopta munita, 
Succinea corbis, and Guppya baud (Dall 1896, Dall and Ochsner 1928). All but Gas- 
trocopta munita are among the 16 species found as fossils in the present study. This 
suggests that at least some species may have entered and/or remained in the caves 
because of the accumulations of bone and shell inside. The numbers of species reported 
as occurring on bones versus those that have not falls short, however, of being signif- 
icantly heterogeneous (x"i = 3.6346, P = .052) between species found as fossils and all 
species recorded on Floreana and Santa Cruz. We have also identified fossil fecal strands 
from Cueva de Kubler that were probably left by one of the larger Naesiotus species, 
indicating that some snails were alive in the cave for at least a short time. To summarize, 
we believe that factors 1, 2, and 4 are important means of entry into fossil caves by 
snails, with factor 2 perhaps being especially important for the various species of 
Naesiotus, whose relatively sturdy shells are better able to withstand the rigors of 
sediment influx. 

Comparison of fossil and historic snail faunas.— EsseniiaWy all fossil records are 
only subsets of the entire fauna being sampled, so it is expected that only a portion of 
the known land snail species from Floreana and Santa Cruz were found in the fossil 
deposits. On Santa Cruz, 1 5 species were found as fossils in or near deposits out of a 
reported total of 34 species in the historic fauna for that island (Dall 1900, 1917, Dall 
and Ochsner 1928, Pilsbry 1931, Odhner 1950, A. G. Smith 1966, 1972, Vagvolgyi 
1977, Coppois and Glowacki 1983, this study). Of the historic fauna of 26 species on 
Floreana (Dall 1896, Dall and Ochsner 1928, Pilsbry 1931, A. G. Smith 1966), only 
three were found as fossils. On both islands, habitat preference probably accounts for 
many of these absences, for numerous species are known only from higher elevations 
than those of the fossil sites. We are not certain, however, why the Floreana fossil sites 
sampled the snail fauna so much more poorly than those of Santa Cruz, although 
perhaps the mode of sedimentary influx, especially the smaller sizes of the catchment 
basins on Floreana, is involved. 

Among the species found as fossils on Santa Cruz, nine had not been reported 
from that island previous to A. G. Smith's visit in 1964. These are Helicina nesiotica, 
Tornatellides chathamensis, Gastrocopta duncana, Succinea corbis, Guppya bauri, 
Habroconus? galapaganus, Retinellal chathamensis, Naesiotus kublerensis, and Nae- 
siotus steadmani. Except for Succinea corbis, which belongs to a taxonomically difficult 



106 

family, and the two Naesiotus, these are small snails that are no more than a few mm 
in their greatest shell dimension. A. G. Smith (1966) added new Santa Cruz records 
for all of these small species except Gastrocopta duncana and Guppya bauri. Our new 
records for Gastrocopta duncana and Guppya bauri consist, respectively, of only one 
and three shells. 

Comparison of the fossil records of snails and vertebrates. —The distinction between 
historic faunas and paleofaunas is more difficult to discern with land snails than with 
vertebrates. Historic vertebrate faunas are based on specimens or field accounts taken 
of living individuals, whereas the historic land snail fauna of Galapagos is based largely 
on shell material, which under favorable conditions may persist intact and relatively 
unchanged for many years after the death of the animal. Thus the "historic" fauna may 
include species that were already extinct when first collected, and therefore we may be 
underestimating the extent of extinction in land snails. Historic faunas of snails therefore 
may be more representative of the natural (pre-human contact) fauna than are vertebrate 
faunas. In this respect, well-known historic faunas of land snails may be more appro- 
priate subjects than birds and other vertebrates for tests of equilibrium ecological 
theories {see Solem [1982] for a recent study). 

The fossil records of vertebrates from Floreana and Santa Cruz are more complete 
samples of the local fauna than those of snails. From both islands, the fossils included 
every species of terrestrial mammal or reptile, including those now extinct. The resident 
land bird faunas of Floreana and Santa Cruz are quite diverse (over 20 species), but 
the fossil record lacks only five species, three of which {Neocrex erythrops, Coccyzus 
melacoryphus, and Dendroica petechia) probably colonized Galapagos relatively re- 
cently, perhaps less than a thousand years ago (Steadman 1986). The fourth species, 
Buteo galapagoensis, is a large hawk that does not live in caves and is not preyed upon 
by bam owls; the absence of the fifth species, the owl Asioflammeus, can be accounted 
for in the same way. 

The main reason that the fossil snails represent a much less complete sample of 
each island's local fauna is probably that the snails were not being concentrated in the 
caves by predators. Therefore, unlike the vertebrates that were being sampled within 
approximately a 1 km radius of the cave (the estimated home range of the bam owl 
Tyto punctatissima), only the snails that lived in the immediate vicinity of the caves 
had an opportunity to be deposited within the caves. 

Vertebrate extinction in the late Holocene of Galapagos occurred mainly or entirely 
in historic times, and can be related circumstantially to human-related impacts. Such 
impacts, especially habitat disturbance, may have affected the present snail faunas. In 
contrast to some cases of vertebrate extinction in Galapagos, direct human predation 
is an unlikely factor in land snail declines. The detrimental, often catastrophic, effects 
of land clearing for agriculture and of introduced mammals on land snail faunas on 
Pacific islands and elsewhere, however, has been noted repeatedly (e.g., Solem 1974, 
1976, Christensen and Kirch 1981a, b. Wells et al. 1983, Neck 1984). Agricultural 
conversion has very likely been detrimental to Galapagos land snails on Floreana, the 
island in the archipelago with the longest history (beginning early in the 1 9th century) 
of human settlement (Slevin 1959). Santa Cruz was not settled until the present century, 
but is now the most heavily populated and visited island, and much of the southern 
part, including areas near the fossil localities, has been converted to agricultural uses 
(Schofield 1973). 

Introduction of exotic organisms, especially mammals, is probably the most per- 
vasive human-caused threat to the native land snails in Galapagos. Feral goats {Capra 
hircus), cattle (Bos taurus), donkeys {Equus asinus), pigs (Sus scrofa), dogs (Canis 
familiaris), and cats (Felis catus) have lived or are living on both Floreana and Santa 
Cruz; and goats, cats, and donkeys remain common today in the vicinity of the Floreana 
fossil sites (Steadman 1986). Cats and dogs probably had no effect on snails, but 
cattle, donkeys, pigs, and especially goats can destroy land snail habitat by removing 
or altering native plant communities through persistent grazing and browsing (Weber 
1971, Hamann 1975). Pigs have the additional destmctive habit of rooting through 



107 



litter and soil; this turning over of the substrate can kill snails directly and, more 
importantly, exposes moist, subsurface refuges to desiccation. Rooting pigs may also 
eat snails that they encounter. 

Introduced rats (Rattus rattus) and mice {Mus musculus) are present in Galapagos. 
Rodent-gnawed shells have been found on islands that have declining land snail faunas 
(e.g., Stokes 1917). Although predation by introduced rodents on land snails is extremely 
likely, it is possible that in some cases they gnaw already dead shells for calcium, as 
they sometimes do on vertebrate bone. Interactions between rodents and living land 
snails deserve intensive investigation. Indications of rodent predation on Galapagos 
fossils are limited to Naesiotus ochsneh, as discussed earlier. 

Although detrimental effects have yet to be reported, introduced snails have been 
recorded from Galapagos (Smith 1966). Replacement of native land snails by intro- 
duced snails has been noted on islands elsewhere (Solem 1974, Christensen and Kirch 
1981a, b), although it is sometimes not clear if these cases involve direct competition 
and replacement or simple occupation by introduced snails of human-modified habitat 
that has become unsuitable for native species. The introduced predatory snails that 
have proven so catastrophic to other island land snail faunas (Hadfield and Mountain 
1980, Clarke et al. 1984) have not yet made an appearance in Galapagos. Introduced 
ants (Lubin 1984) are also potential predators on native land snails (Solem 1976). 

Although direct evidence of impacts of humans and introduced mammals is lack- 
ing, except for possible rodent predation, there are a number of indications that such 
influences exist. Despite the efforts of Ochsner in 1905-1906 and A. G. Smith in 1964, 
Gastrocopta duncana and Guppya bauri, both reported here as fossils, were not pre- 
viously reported from Santa Cruz. Naesiotus cymatias, N. ochsneri, N. blombergi, and 
many of the smaller species found as fossils have been reported from historic collections 
on Santa Cruz, although generally from higher elevations than the fossil sites. Naesiotus 
kublerensis and Naesiotus steadmani are known only from limited shell material and 
may be extinct. Naesiotus cymatias on Santa Cruz and Naesiotus galapaganus on 
Floreana are rare in historic collections, but both are ubiquitous and extraordinarily 
abundant as fossils. 

Dall long ago warned of the vulnerability of the Galapagos land snail fauna, citing 
gaps in the understanding of the Hawaiian fauna "because the sheep and goat have 
preceded the investigator" (Dall 1896:29). Dall's warning was repeated by A. G. Smith 
(1966). The DeRoy family, which has lived on Santa Cruz since 1958, has told DWS 
(personal communication 1978, 1980) that it is much more difficult to find living 
examples of most land snails today on Santa Cruz than it was only two decades ago. 
Coppois and Glowacki (1983) made the general observation (supported in Coppois 
[1984]) that some Santa Cruz bulimulid snails "are extinct or on their way to extinc- 
tion." Extinction is difficult to prove in these land snails because living snails can be 
overlooked owing to their inconspicuous color, size, and habits. Regardless, there are 
clear signs of reductions in range and abundance. 

Acknowledgments 

Funds for field work were provided by the Smithsonian Institution's Fluid Research 
Grants and Scholarly Studies Program, through the efforts of D. Challinor, S. L. Olson, 
and S. D. Ripley. Museum work was funded by the National Geographic Society (Grant 
2088 to DWS), Smithsonian Fellowships, and a National Science Foundation Grant 
(DEB-7923840 to P. S. Martin). Field work was done with the assistance and coop- 
eration of Parque Nacional Galapagos (M. Cifuentes, F. Cepeda) and Charles Darwin 
Research Station (C. MacFarland, H. Hoeck, D. Duffy, F. Koster, G. Reck), as well as 
numerous field companions. A. Long and R. Stuckenrath provided radiocarbon ages. 
Curators and staffs of these collections allowed access to and (for CAS and MCZ) loans 
of specimens (ANSP-G. M. Davis; CAS-T. M. Gosliner and B. Roth; MCZ-K. J. 
Boss; National Museum of Natural History— J. Rosewater). SMC carried out most of 
his contribution to this study while a Research Associate of the Department of Inver- 



108 



tebrate Zoology of the National Museum of Natural History, Smithsonian Institution. 
He thanks the staff of the Division of Mollusks for their aid and forbearance. The 
manuscript has been improved by thorough reviews and comments by B. Roth and C. 
Christensen on an earlier draft. Figure 1 was drawn by E. Paige. Photographs for Figures 
1-2 are by V. Krantz. This is Contribution Number 381 of the Charles Darwin Foun- 
dation for Galapagos and Contribution Number 480 of the New York State Science 
Service. 

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TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 



Volume 21 Number 7 pp. 111-126 5 December 1986 

Callorhinus gilmorei n. sp., (Carnivora: Otariidae) from the 

San Diego Formation (Blancan) and its implications for . . iCZ 

otariid phylogeny LIBRA F?y 

Annalisa Berta DEC T 9 

Department of Biology. San Diego State University, San Diego, CA 92182 USA ^^ 

Thomas A. Demere 

Department of Paleontology, San Diego Natural History Museum, P.O. Box 1390, 
San Diego, CA 92112 USA 

Abstract. A new species of fur seal, Callorhinus gilmorei, described from the San Diego Formation 
of southern California and Mexico, fills a critical stratigraphic and evolutionary gap in our knowledge 
of otariids. This Late Pliocene (Late Blancan) occurrence of Callorhinus represents the earliest record 
of modem otariid genera. Mandibular and dental characters distinguish Callorhinus gilmorei from the 
living northern fur seal, C ursinus. 

Cladistic analysis supports a sister group relationship between Callorhinus and the Hemphillian 
fur seal "'Thalassoleori" macnallyae. Relationships among Arctocephalus species are unresolved. Re- 
evaluation of Hydrarctos lomasiensis from the Pliocene of Peru suggests that it is the primitive sister 
taxon of all modem otariids. Modem fur seals and sea lions form separate monophyletic groups. 

Introduction 

The poor representation and isolated occurrences of the Otariidae (fur seals and 
sea lions, following the classification of Repenning and Tedford 1977) in the fossil 
record inhibits our understanding of phylogenetic relationships within this group. The 
earliest known otariid is Pithanotaria starri Kellogg 1925 from the Clarendonian (late 
Middle and early Late Miocene; 11-12 MYA) of California. Better preserved and more 
complete material of a younger otariid, Thalassoleon mexicanus Repenning and Ted- 
ford, 1977 is known from the Hemphillian (late Late Miocene; 5-8 MYA) of Mexico. 
A second species of Thalassoleon, T. macnallyae Repenning and Tedford 1977, from 
the late Hemphillian (late Late Miocene and Early Pliocene; 5-6 MYA) of California, 
is less well known. At this point the record of otariids becomes scant, and as noted by 
Repenning and Tedford a major gap exists between Thalassoleon at about 5 MYA 
and the more diverse otariid faunas of the Pleistocene and Recent. These authors 
suggested that within this gap, which involves most of the Blancan (Pliocene; 2-5 
MYA), lies the history of fur seal diversification and the origin of sea lions. 

The modem fur seals include the monotypic northern fur seal, Callorhinus ursinus 
(Linnaeus), and the polytypic southern fur seal, Arctocephalus (F. Cuvier), with eight 
species currently recognized (Repenning et al. 1971). Until now, the earliest record of 
a fur seal referred to a modem genus was based on a partial skeleton from the Pliocene 
of Peru, ""Arctocephalus"' (Hydrarctos) lomasiensis de Muizon, 1978. However, we 
question this generic assignment and suggest that the subgenus Hydrarctos be elevated 
to generic rank to include this primitive taxon. 

We provide evidence of a new fur seal from the Blancan of Califomia and Mexico 
which represents the oldest known fossil otariid referable to a modem genus. This new 
species is described from a partial skeleton lacking the skull, collected from the Upper 



112 

Table 1. Recent otariids studied. (*, skull(s) only; all others include skull(s) and skeleton(s)). 

Taxa Number of specimens 

Callorhinus ursinus 20 

Arctocephalus australis 1 

Arctocephalus forsteri 3 

Arctocephalus galapagoensis 2 

Arctocephalus gazella 1 

Arctocephalus philippii 1 

Arctocephalus pusillus 1 

Arctocephalus townsendi 3 

Arctocephalus tropicalis* 1 

Eumetopias jubata 8 

Neophoca cinerea 2 

Otaria byronia 7 

Phocarctos hookeri 7 

Zalophus californicus 14 



Pliocene San Diego Formation. In addition, a number of isolated dentaries, maxilla 
and postcranial elements from the San Diego Formation are referred to this new 
species. Included in this referred material is a fragmentary lower jaw, previously de- 
scribed by Burleson (1948) and Repenning and Tedford (1977). 

In the initial stages of this study we were primarily concerned with the identity 
and relationship of this new fur seal. However, as our study progressed, we soon realized 
that in order to determine systematic affinities of the fossil taxon we needed to un- 
derstand the broader phylogenetic relationships among all otariids. From this we ex- 
panded our study to include a cladistic analysis of all living and some fossil otariids. 

Recent otariids examined in this study are listed in Table 1 . Additional osteological 
data for extant and fossil otariids were obtained from the literature (de Muizon 1978, 
Repenning et al. 1971, King 1960, Repenning and Tedford 1977, Scheffer 1958, Sivert- 
sen 1954). 

The following institutional abbreviations are used in the text. SDSNH, San Diego 
Natural History Museum, San Diego, California. LACM, Natural History Museum of 
Los Angeles County, Los Angeles, California. USNM, National Museum of Natural 
History, Smithsonian Institution, Washington, D.C. 

Systematic Paleontology 

Family Otariidae Gill, 1866 

Subfamily Arctocephalinae von Boetticher, 1934 

Genus Callorhinus Gray, 1859 

Callorhinus gilmorei, new species 

Figures 1,2 

Pithanotaria sp., Burleson, 1948:248. 

cf. Callorhinus ursinus, Repenning and Tedford, 1977:73. 

Holotype. —SDSNH 25176, partial young adult female skeleton including: left P 
and P-, right upper C, I' °'^-, and P', right I,, right dentary with P2_3 and M,; left L and 
P,_3; right and left innominates each lacking posterior one-third of pubis and ischium; 
ribs and rib fragments; lumbar, thoracic, and caudal vertebrae and fragments; all as- 
sociated and from the same individual. 

Type locality. —SDSNH locality 3 1 74-D, San Diego, San Diego County, California; 
San Diego Formation, lower member (of Demere 1983); collected by B. O. Riney and 
R. A. Cerutti, 9 August 1982. 

Known distribution. —Late Pliocene (late Blancan), of California and Mexico. 

Referred material and localities. —SDSNH 26239, partial right dentary with P2_3 
and Ml from La Joya, Baja CaHfomia Norte, Mexico (SDSNH locality 3125), San 
Diego Formation (lower member), collected by A. B. Brockmeir; LACM 1 15253, left 



113 





-?«A..f<n 



Figure 1. Callorhinus gilmorei, n. sp., Holotype: A-D, SDSNH 25176, (A) medial, (B) occlusal, and (C) 
lateral views of right dentary with P,.,, M,, (D) lingual view of right P,. Referred material: E-H, LACM 
1 15253, (E) medial, (F) occlusal, and (G) lateral views of left dentary with P3, SDSNH 25531, (H) occlusal 
view of right maxilla with P'^. Scales = 1 cm. 



114 





Figure 2. Callorhinus gilmorei, n. sp. Holotype: A-C, SDSNH 25176 (A) anterior and (B) lateral view of 
lumbar vertebra (L2), and (C) lateral view of left innominate. Scales = 1 cm. 



dentary with C and P3 from Ward Road (LACM locality 4294), San Diego, San Diego 
County, California, San Diego Formation (lower member), collected by A. B. Brock- 
meir; LACM 4323, partial left dentary with P., P4, and Mi from Reynard Way (LACM 
locality 1072), San Diego, San Diego County, California, San Diego Formation (lower 
member), collected by C. W. Kennell; SDSNH 25554, edentulous right dentary, SDSNH 
25535, partial left dentary with C, SDSNH 25531, partial right maxilla with P^"^ and 
right jugal, and SDSNH 25616, left P^ in maxillary fragment, all from Mission Hills 
Quarry (SDSNH locality 3206), San Diego, San Diego County, California, San Diego 
Formation (lower member), collected by SDSNH field party. 

Diagnosis.— A species of Callorhinus with a long, shallow pterygoid process on 
the mandible that does not form a medial shelf; with double-rooted lower third and 
fourth premolars and closely spaced upper first and second molars; small third upper 
incisor with oval cross section; and dorsally directed anterior margin of the mandibular 
foramen. 

Etymology.— ThQ name honors the late Dr. Raymond M. Gilmore for his lasting 
contributions to the field of marine mammalogy. 

Description. —Except where noted, the following description refers to the holo- 
type. The dentary has a gently sloping symphyseal area (Fig. 1). Two large mental 
foramina are below P^ and P3, just above the midline of the ramus; smaller foramina 
mark the anterior one-half of the jaw. The mandibular foramen has a dorsally directed 
anterior margin (Fig. 3). The coronoid process is broad at the base but tapers to a 
relatively high, narrow dorsal margin. The pterygoid process of the mandible is long 
and shallow with a reduced medial surface that slopes ventromedially and is not pro- 
duced into a shelf as in living Callorhinus. The articular condyle is at the same level 
as the base of the ascending ramus. The cheektooth row is short relative to the distance 
from P, to the ascending ramus as shown on Figure 4. The horizontal ramus is elongate 



115 



Table 2. Mandible and lower tooth measurements for Callorhinus gilmorei (a, alveolus only; e, estimated; 
*, holotype). 





USNM 


SDSNH* 


SDSNH 


SDSNH 


SDSNH 


LACM 


LACM 


Measurement 


184065 


25176 


26239 


25554 


25535 


115253 


4323 


Depth of mandible behind M, 




15.8 


16.5 


17.0 


15.5 


18.9 


15.5 


Length of toothrow P.-M, 




40.1 


— 


42.5 


35.6e 


41. le 


33.4e 


Height of mandible 




36.4 


— 


— 











C, anteroposterior length 


10.9 


8.6a 


— 


— 


13.5 


10.8 





C, transverse width 


8.7 


— 


— 





8.9 


7.4 





Pi, anteroposterior length 


5.4a 


5.7a 


— 


5.0a 


— 





.. 


P,, transverse width 


4.3a 


4.1a 


— 


3.0a 


— 








Pj, anteroposterior length 


7.6a 


5.5 


6.1 


6.5a 


— 


10.7a 


5.3 


P,, transverse width 


4.8a 


4.0 


4.7 


3.5a 


— 





3.0 


P3, anteroposterior length 


7.4a 


6.5 


6.5 


8.3a 


— 


6.7 


6.8a 


P3, transverse width 


3.8a 


4.2 


4.8 


4.0a 


— 


4.7 


3.4a 


P4, anteroposterior length 




6.7a 


6.5a 


7.7a 


— 


7.9a 


5.5 


Pj, tranverse width 




3.4a 


3.0a 


3.4a 


— 


4.0a 


3.5 


M|, anteroposterior length 




7.4 


6.7 


8.4a 


— 


8.2a 


6.1 


M,, transverse width 




4.1 


3.9 


3.6a 


— 


3.9a 


3.8 



and slender in the type, and in SDSNH 26239, SDSNH 25554 and LACM 4323, which, 
presumably represent females. The robust jaw and larger canines in SDSNH 25535 
and LACM 1 1523 suggest that these specimens represent males. 

Isolated lower incisors are associated with the type jaw. The top one-half of the 
crown of 1 1 is worn flat. The tooth is single-cusped, triangular in cross section, and has 
a strongly compressed root. L is larger, with a high medial cusp and a low basal cusp 
that slopes posteromedially. The small size of the canine alveolus in the type and 
SDSNH 25554 suggests that the canine was relatively small and slender in contrast to 
the large, robust canine in SDSNH 25535 and LACM 1 15253. Again these differences 
are attributed to sexual dimorphism. 

Relative to the size of the jaw, the check teeth are proportionately small and high 
crowned with prominent lingual cingula (Table 2, Fig. 1). P, has a large central cusp 
preceded by a small accessory cusp. The tooth crown slopes posteriorly. P. is single- 
rooted with a vertical sulcus on the labial surface of the root. There is a small anterior 
accessory cusp on P.-a. The left P, is double-rooted with strongly divergent roots, 
whereas the right P3 is single-rooted with a vertical sulcus on the lateral and medial 
surfaces of the root. This tooth is double-rooted in LACM 4323, LACM 115253, 
SDSNH 25554, SDSNH 25535 and single-rooted in SDSNH 26239. P4 is double- 
rooted in all specimens except SDSNH 26239. Apart from its larger size, P4 is very 
similar to P3. M, is double-rooted in all specimens except SDSNH 25535 in which the 
alveolus indicates a single root. The tooth consists of a central cusp that is strongly 
inclined posteriorly and followed by a small accessory cusp on the tooth heel. The 
anterior accessory cusp is indistinct in the holotype but prominent in SDSNH 26239. 

Isolated upper teeth were found in association with the type jaw and are presumed 
to be from the same individual. A tooth broken near the base of the crown is identified 
as either I' "'- based on lateral compression of the root. I^ is small and caniniform with 
a strongly curved root and an oval cross section. The slender upper canine displays 
less curvature than the corresponding lower tooth. The anterior premolars, P'"\ are 
single-rooted and lack accessory cusps. P- differs from P' in its slightly larger size and 
vertical sulcus on the lateral and medial surfaces of the root. 

A right maxillary with P^"^, SDSNH 25531, and a left P^ in a maxillary fragment, 
SDSNH 25616, probably from the same individual, are provisionally referred to this 
species. In occlusal view, the cheek tooth row converges at P-"^ and diverges at M', 
creating a sinuous toothrow (Figs. 1, 5). P-""* and M'~' are double-rooted. The teeth are 
proportionally small and high crowned with strong lingual cingula. No accessory cusps 
are developed. Judging from the alveoli, M' - were positioned close together. Mea- 



116 





B 



Figure 3. Diagram showing shape of mandibular foramen in (A) Callorhinus ursinus and (B) Arctocephalus 
townsendi. Arrow indicates slope of anterior margin of mandibular foramen. 



surements are as follows: P^, anteroposterior length 5.8 mm, transverse width 4.3 mm; 
P^, anteroposterior length 6.3 mm, transverse width 4.3 mm. 

That the type specimen was a young adult is indicated by the only slightly worn 
dentition and the lack of epiphyses on the innominates and vertebrae. Although most 
of the pubis and ischium is missing, the pubis appears to be relatively broad dorso- 
ventrally, characteristic of a female. This specimen has a broad, low pectineopsoal 
process projecting ventrally from the ilium at the acetabulum (Fig. 2). The holotype 
includes the shafts and heads of two ribs, the shafts of two ribs, the heads of three ribs, 
the centra of three thoracic, two lumbar (L2 and 3?) (Fig. 2), and four caudal vertebrae. 

Discussion. — Callorhinus gilmorei appears to be more primitive than the living 
northern fur seal, C. ursinus on the basis of dental and mandibular characters. In C 
gilmorei, P3_4 are usually double-rooted by contrast to their single-rooted condition in 
C. ursinus. In addition, the pterygoid process of the mandible in C. gilmorei has a 
ventromedially sloped medial surface rather than the strongly produced medial shelf 
characteristic of C. ursinus. Also, in C. gilmorei M^-^ are positioned close to one another, 
whereas in C. ursinus M'~^ are separated by a persistent diastema. 

Repenning and Tedford (1977) commented on the similarity between Thalassoleon 
macnallyae and Callorhinus and suggested that a large sample of the former species 
might provide evidence for the origin of the genus Callorhinus from T. macnallyae. 
As noted by Repenning and Tedford similarities between these taxa include smaller 
cheekteeth, greater ornamentation of the medial lip of the ectotympanic bone, postcruci- 
ate sulcus separating postcruciatus and lateral gyrus, unconvoluted and relatively nar- 
row gyrus ectosylvius posterior, and posterior position of the frontal-parietal suture. 
Unfortunately, neither a cranium nor endocranial cast are available for the fossil species 
Callorhinus gilmorei. The following characters distinguish C gilmorei from T. mac- 
nallyae: considerably smaller size, small V with oval cross section and M'~^ positioned 
close together. 

Our study offers additional support for a closer relationship between Callorhinus 
and Thalassoleon macnallyae than between Callorhinus and Thalassoleon mexicanus, 
or between Callorhinus and Arctocephalus. Thalassoleon mexicanus is more primitive 
than T. macnallyae in its possession of smaller vertebral foramina, less ornamentation 
of the medial edge of the ectotympanic and lack of fusion of the tibia and fibula. 
Arctocephalus, together with all sea lions, is more derived than either Thalassoleon or 
Callorhinus in having a mandibular foramen with a ventrally directed anterior margin. 

Although relationships among Arctocephalus species are largely unresolved, and 
will be discussed below, Callorhinus gilmorei can be readily distinguished from A. 
townsendi, the only modem fur seal in addition to C ursinus with a known distribution 
along the Pacific coast of North America. In C gilmorei the length of the cheek toothrow 
relative to the distance from P, to the ascending ramus is short, rather than long as in 
A. to\~ isendi (Fig. 4). Additionally, in the fossil species the pectineopsoal process on 
the iliu 1 is broad and low rather than narrow and projecting as in A. townsendi. Finally, 
in C gi norei the pterygoid process of the mandible is long and shallow rather than 



90, 



80, 
70J 



60_ 



117 




Thalassoleon 

* mexicanus 

Hydrarctos 
▲ lomasiensis 

Callorhinus 
o gilmorei n. 

• ursinus 



0^ 



o 
o 



o«.' 



sp. 



Arctocephalus 
V austral is 
D galapagoensis 
philippii 
4 pusillus 
 townsendi 



1 



T" 

20 



% 



T- 
30 



40 



50 



Figure 4. Scatter plot of length of lower cheek toothrow relative to length of horizontal ramus among fur 
seals. 



short and deep as in A. townsendi. Earlier, Burleson (1948) noted that a mandibular 
ramus (LACM 4323) from the San Diego Formation, here referred to C. gilmorei, could 
be distinguished from A. townsendi in having P4 and M, on the dorsal crest of the 
ramus rather than on the medial side of the crest as in /I. townsendi. Our study of other 
dentaries referred to C. gilmorei confirms Burleson's observation. 

Implications For Otariid Phylogeny 

Traditionally, modem otariids have been grouped into two subfamilies: Otariinae 
(sea lions) and Arctocephalinae (fur seals) {see Scheffer 1958). Repenning et al. (1971) 
suggested that subfamilial distinction is unwarranted since they were unable to find 
osteological characters that consistently separated these two groups. Repenning and 
Tedford (1977) retained the "Otariinae" and "Arctocephalinae'' only as nomenclatural 
conveniences and did not use them in their formal classification. Our analysis provides 
support for the traditional view that fur seals and sea lions belong to different groups. 
Sea lions, which include five living, monotypic genera, Zalophus, Neophoca, Phocarctos, 
Otaria, and Eumetopias, are recognized by most workers as a monophyletic group. 
The monophyly of fur seals, which include the living genera Arctocephalus and Cal- 
lorhinus, has been questioned, most recently by Repenning and Tedford (1977) and de 
Muizon (1978). 



118 




A 




B 



Figure 5. Diagram of palate showing outline of upper cheek toothrow in (A) Zalophus californicus and (B) 
Arctocephalus pusillus. 



Interpretations of otariid relationship are summarized in Figure 6. Both previous 
studies and this one view sea hons as monophyletic. Traditionally, fur seals have been 
recognized as polyphyletic, although this study distinguishes modem fur seals as mono- 
phyletic. While Repenning and Tedford (1977) recognized Pithanotaria as the earliest 
known otariid, they suggested that the better known, more derived fossil taxon Thal- 
assoleon might be ancestral to both lineages of living fur seals and the living sea lions. 
De Muizon (1978) used the distinctive morphology of the baculum to argue that 
Thalassoleon and Callorhinus are more closely related and should be recognized as a 
separate subfamily, the Callorhininae. 

Cladistic analysis was used to evaluate relationships among all living and some 
fossil otariids, using the characters discussed in the Appendix. Fossil otariids studied 
include Pithanotaria starri {CXdiYQndonidir]., California), Thalassoleon mexicanus (Hemp- 
hillian, Mexico), Thalassoleon macnallyae (latest Hemphillian, California [? Blancan, 
Repenning, personal communication]) and ''Arctocephalus'^ (Hydrarctos) lomasiensis 
(Pliocene, Peru [Montehermosan or Chapadmalalan?]). The polarity of characters was 
determined by outgroup comparison using the most primitive known otarioid (includes 
fur seals, sea lions, walruses and their extinct relatives), Enaliarctos mealsi Mitchell 
and Tedford (1973) from the Late Oligocene/Early Miocene of California. Published 
descriptions of this species (Mitchell and Tedford 1973, Barnes 1979) were supple- 
mented by an evaluation of unpublished enaliarctid material housed in the Emlong 
collection at the National Museum of Natural History, Smithsonian Institution, Wash- 
ington, D.C. and the U.S. Geological Survey (Denver). An attempt was made to use 
only material that could be definitely assigned to Enaliarctos; although those characters 
that were present among all enaliarctids (including Enaliarctos and Pinnarctidion) were 
noted. 

In our analysis we attempted to account for variation by examining, when possible, 
more than just a single specimen of a taxon (Table 1). Only those characters that 
withstood careful scrutiny were used in the analysis. A total of 4 1 osteological, soft 
anatomical and behavioral characters were selected. We acknowledge the fact that while 
some of these characters are undoubtedly related, both functionally and phyletically 
(e.g., characters 5, 6, 7 tooth and root simplification), our recognition of these as separate 
characters has not biased their weighting in the analysis. We independently examined 
those special cases where double-weighting of characters may have applied, and found 
no difference in the branching pattern than that obtained by considering these characters 
separately. 

Characters were analyzed and minimum-step cladograms generated by computer 
using the PHYSYS program written by J. S. Farris. Cladograms were constructed by 



119 



o.<-<>' ^vo^ 




Repenning and Tedford, 1977 



"^^'' ..sO^^° 



,-.<-^^ ^v^^ 




de Muizon, 1978 




This study 



Figure 6. Cladistic representation of previous and present interpretations of otariid relationships. 



120 



a 

u 

a 

I 

■*-» 

X 
u 




u 
u 



u 

•c 

u 



u 
o 

u 

■*-• 
A 

CO 

IH 
U 

s 

;^ 

cfl 

•s 



e 

o 



C 
u 
o 
u 

Cm 

o 



JS 
</i 

c 
o 

o " 

2 g? 

e 8 

o ^^ 

"2 "^ 
J3 c 
(J « 






121 

the Wagner procedure (Farris 1970) and its global branch swapping option (Mickevich 
1978). One Wagner and a single Pimentel tree were obtained, with the Wagner tree 
being shorter. Several modifications of the computer generated trees necessitated con- 
struction of a consensus cladogram based in large part on the Wagner tree (Fig. 7). 
These modifications involve two characters ( 1 4, 1 5) that the computer analysis showed 
to be derived for both fur seals and sea lions, prior to divergence of these two groups. 
Although the analysis indicated that sea lions must have lost these characters, we feel 
that it is more parsimonious to consider that they were derived only once in the modem 
fur seals. 

Monophyly of the Otanidae and its distinction from Enaliarctos is supported by 
four shared derived characters: absence of lacrimal foramen, nasolabialis fossa, fissiped- 
like dentition, and presence of large, well-developed supraorbital processes (characters 
1-4). Pithanotaria starii, the most primitive otariid analyzed is distinguished from all 
other otariids in lacking M- (character 8). The fossil otariid, Thalassoleon mexicanus 
and all other otariids share a single derived character, a simple lateral upper incisor 
(character 5). "'Arctocephalus'' (Hydrarctos) lomasiensis, fur seals and sea lions can be 
distinguished from Thalassoleon mexicanus by five synapomorphies (characters 6, 7, 
9, 12, 13). Our analysis oVArctocephalus"" (//.) lomasiensis suggests that it should not 
be recognized as a species of Arctocephalus. This taxon is recognized here as a primitive 
otariid distinct from the Arctocephalus-Callorhinus clade. Based on this we recommend 
elevation of the subgenus Hydrarctos to generic status. 

In this analysis advanced otariids share a single derived character— calcaneum with 
well-developed secondary shelf of the sustentaculum (character 11). Although rela- 
tionships among fur seals are here represented as an unresolved polychotomy, three 
separate groups can be identified which share the following two derived characters: 
narrow basioccipital, and I^ with oval cross section (characters 14, 15). The fossil otariid 
Thalassoleon macnallyae and the northern fur seal, Callorhinus ursinus share a sister 
group relationship that is supported by four shared derived characters (characters 23, 
32, 33, 34). The identity of the fossil fur seal described in this paper as a species of 
Callorhinus is supported by mandibular and dental characters as previously discussed. 
Callorhinus gilmorei is more primitive than C. ursinus in having a long, shallow pter- 
ygoid process that does not form a medial shelf, P3_4 that are usually double-rooted, 
and M'"- positioned close together. 

Relationships among Arctocephalus species are less well resolved, owing to a high 
degree of convergence among several of the characters (e.g., characters 18, 26, both of 
which appear to be independently derived among the various fur seal and sea lion 
clades). In an earlier discussion of arctocephaline relationships, Repenning et al. ( 1 97 1 ) 
recognized A. pusillus and A. gazella as distinct from all other Arctocephalus species. 
Our analysis provides further support for this interpretation. Although A. pusillus is 
distinguished from all other species of the genus by three characters, two of these are 
convergences (characters 18, 20) that occur in other Arctocephalus species. Arctocepha- 
lus townsendi, A. australis, A. philippii, A. galapagoensis, and A. forsteri are separated 
from A. gazella and A. tropicalis in having a short, deep pterygoid process on the 
mandible (character 25). 

Recognition of sea lions as a natural group is supported by osteological (19, 27, 
28, 29), soft anatomical (31, 35, 36) and behavioral (37) characters. Eumetopias, Neo- 
phoca, Phocarctos and Otaria are more derived than Zalophus in their possession of 
a single derived character, apex of baculum further expanded laterally (character 30). 
The southern sea lions, Otaria, Neophoca, and Phocarctos share well-developed ac- 
cessory cusps on cheek teeth and a deep palate (characters 20, 39). The most derived 
sea lions, Otaria and Phocarctos share two derived characters, both of which represent 
convergences elsewhere on the cladogram. 

A classification of modem genera in the Family Otariidae developed in this paper 
is presented in Table 3. Fossil otariids, Pithanotaria starri, Thalassoleon mexicanus, 
and Hydrarctos lomasiensis are recognized as primitive members of the Otariidae. 
Modem fur seals and sea lions are defined here as belonging to separate monophyletic 



122 

Table 3. Classification of Recent Otariidae. 



Order Camivora Bowdich, 1821 
Family Otariidae Gill, 1866 
Subfamily Arctocephalinae von Boetticher, 1934 

Arctocephalus Geoffroy and Cuvier, 1826 

Callorhinus Gray, 1859 
Subfamily Otariinae von Boetticher, 1934 

Eumetopias Gil\, 1866 

Otaria Peron, 1816 

Neophoca Gray , 1866 

Phocarctos VtXers, 1866 

Zalophus Gray, 1859 



groups and designated as subfamilies. The Arctocephalinae, which includes the modem 
fur seals, Arctocephalus and Callorhinus, as well as the fossil fur seal ""Thalassoleon'' 
macnallyae is defined by two derived characters— rectangular basioccipital, and P with 
oval cross section. Although we do not recognize the Callorhininae at the subfamilial 
level, our analysis does support the close relationship between Thalassoleon macnallyae 
and Callorhinus originally suggested by de Muizon (1978). Pending further analysis of 
the Callorhinus-Arctocephalus clade, we have chosen not to formally designate this 
monophyletic group. More derived otariids, the sea lions are grouped in the Otariinae, 
which includes Eumetopias, Neophoca, Phocarctos, Otaria, and Zalophus. The follow- 
ing derived characters distinguish this group: M' single-rooted, cheektooth row straight, 
humerus stout, pectoral crest directed toward midpoint of distal articulation, apex of 
baculum broad with keels, more convoluted neopallium, sparse underfur, sucking louse 
host specificity, and strongly thigmotactic behavior. 

Conclusions 

A new fur seal, Callorhinus gilmorei n. sp., from the Late Pliocene of California 
and Mexico represents the oldest fossil otariid referable to a modem genus. As the only 
nominal Blancan-aged otariid from North America, this taxon helps to fill a gap in the 
fossil record of the group. 

The new fur seal shares numerous dental and mandibular characters with the living 
Northern fur seal Callorhinus ursinus while retaining several primitive characters such 
as double-rooted cheekteeth. 

Cladistic analysis utilizing 41 osteological, soft anatomical and behavioral char- 
acters supports monophyly of the family Otariidae. The Late Oligocene/Early Miocene 
genus Enaliarctos represents the primitive sister taxon of all otariids. The sea lions and 
modem fur seals represent separate monophyletic groups. The Peruvian fossil fur seal 
''Arctocephalus^' (Hydrarctos) lomasiensis is sufficiently primitive to warrant placing 
it in the newly elevated genus Hydrarctos. The suggested sister group relationship 
between Callorhinus ursinus and ''Thalassoleon'" macnallyae indicates the need of a 
new generic concept for the latter species. This relationship also points to the antiquity 
of this group of fur seals, and serves to highlight the lack of a recognized Arctocephalus 
ancestor. Unfortunately, the analysis failed to resolve the confusing relationships be- 
tween taxa presently grouped in the genus Arctocephalus. 

Acknowledgments 

We thank Lawrence G. Bames (LACM), Charles A. Repenning (U.S. Geological 
Survey, Denver), James G. Mead and Clayton E. Ray (USNM) for permission to study 
specimens in collections under their care. Travel funds to study collections were pro- 
vided by Sigma Xi and the Smithsonian Institution. Daryl Domning, Clayton E. Ray 
and Charles A. Repenning critically reviewed this manuscript. We are especially grateful 
to Rep, who "sweated through innumerable earlier versions trying to make it into 
something he could understand." 



123 



The Gersten Companies of Chula Vista, California, are acknowledged for permit- 
ting and supporting the collection of fossils (including the holotype specimen) on their 
property. In addition the Planning Department, City of Chula Vista, and especially 
Doug Reid of that office are to be commended for realizing the significance of paleon- 
tological resources within their jurisdiction. 

Several of the specimens discussed in this paper were collected under National 
Geographic Society Grant 2754-83 to Thomas A. Demere. 

Special thanks are extended to Joseph and Joan Parker of Coronado, California, 
and to the J. W. Sefton Foundation, San Diego, California, for their continued support 
of fossil vertebrate studies. 



Literature Cited 



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(Mammalia: Otariidae) from Pyramid Hill, 
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seum of Los Angeles County, Contributions in 
Science 318:1-41. 

Burleson, G. L. 1948. A Pliocene pinniped from 
the San Diego Formation of southern Califor- 
nia. University of California Publications in 
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Demere, T. A. 1983. The Neogene San Diego 
Basin: a review of the marine Pliocene San 
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and R. J. Steel (eds.). Cenozoic Marine Sedi- 
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Farris,J.S. 1970. Methods for computing Wagner 
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Kellogg, R. 1925. New pinnipeds from the Mio- 
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the Pacific Coast of North America. Carnegie 
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Kim, K. C, C. A. Repenning, and G. V. Morejohn. 
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Guelph, Guelph, Canada, 1972. Rapports et 
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549. 

King, J. E. 1960. Sea-lions of the genera A^6'o/7/?oca 
and Phocarctos. Mammalia 24(3):445-456. 

. 1983. Seals of the World. 2nd edition. 

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Lyon, G. M. 1937. Pinnipeds and a sea otter from 
the Point Mugu shell mound of California. 
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Michkevich, M. F. 1978. Taxonomic congruence. 
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Mitchell, E. D. 1968. The Mio-Pliocene pinniped 
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. 1975. Parallelism and convergence in the 

evolution of Otariidae and Phocidae: Sympo- 
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versity of Guelph, Guelph, Canada, 1972. 
Rapports et Proces-Verbaux des Reunions, 
Conseil international pour I'exploration de la 
mer 169:12-26. 
— , and R. H. Tedford. 1973. The Enaliarc- 



tinae. A new group of extinct aquatic Camivora 
and a consideration of the origin of the Otari- 
idae. Bulletin of the American Museum of Nat- 
ural History 151(3):201-284. 

Morejohn, G. V. 1975. A phylogeny of otariid 
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Rapports et Proces-Verbaux des Reunions, 
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mer 169:49-56. 

Muizon, C. de. 1978. Arctocephalus (Hydrarctos) 
lomasiensis, subgen. nov. et nov. sp., un nouvel 
Otariidae du Mio-Pliocene de Sacaco (Perou). 
Institut Fran9ais d'Etudes Andines, Bulletin 7 
3-4:168-188. 

Repenning, C. A., R. S. Peterson, and C. C. Hubbs. 
1971. Contributions to the systematics of the 
southern fur seals, with particular reference to 
the Juan Fernandez and Guadalupe species. 
Pp. 1-34 in W. H. Burt (ed.). Antarctic Pin- 
nipedia. Antarctic Research Series 18. 

, and R. H. Tedford. 1977. Otarioid seals 

of the Neogene. U.S. Geological Survey Profes- 
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Robinette, H. R., and Stains. H. J. 1970. Com- 
parative study of the calcanea of the Pinnipe- 
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Scheffer, V. B. 1958. Seals, Sea Lions, and Wal- 
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Sivertsen, E. 1954. A survey of the eared seals 
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241. 



124 



Note Added in Proof 



The framework under which this research was undertaken assumed a working hypothesis of pinniped 
diphyly. Repenning and Tedford's (1977) definition of the Otarioidea as including the Enaliarctidae, Otariidae, 
Odobenidae, and the Desmatophocidae was followed. Recent compelling evidence (Wyss, in prep.) casts 
doubt on pinniped diphyly and argues that the otarioids are not a natural group and are nested within the 
Pinnipedia which includes the above mentioned families and the Phocidae. 

While we support relationships among members of the Otariidae proposed herein we acknowledge the 
fact that several basal characters used to separate the Otariidae from Enaliarctos are also found among other 
pinnipeds. 

Appendix 

Definitions and evaluations of the characters used in the cladistic analysis. 

1. Lacrimal foramen absent 

Presence of the lacrimal foramen in enaliarctids distinguishes them from all other otarioids (Mitchell 
and Tedford 1973) with the exception of some allodesmids (Repenning, personal communication). 

2. Supraorbital processes large and well-developed 

The presence of large supraorbital processes, especially strong in adult males, is diagnostic of the 
Otariidae and distinguishes them from the Enaliarctidae (Repenning and Tedford 1977). 

3. Nasolabialis fossa absent 

The nasolabiahs fossa described by Mitchell and Tedford (1973:232, 234) as a triangular, shallow 
fossa on the side of the snout is found in enaliarctids. The absence of this fossa is a derived condition 
in otarioids. 

4. Carnassials absent 

The enaliarctids can be distinguished from all other otarioids in their possession of a fissiped-like 
dentition in which P"* has a protocone or protocone shelf, and M, has a talonid. A homodont 
dentition is derived and characteristic of later otarioids. 

5. P simple 

A simple lateral upper incisor characterizes most fossil and modem otariids. Pithanotaria starri 
shows the primitive ursine condition, in which F displays a posterior broadening of the crown near 
the base with a distinct posteromedial lingual cingulum preserved in a referred specimen (Repenning 
and Tedford 1977). 

6. P2, single-rooted 

The development of single-rooted cheekteeth, a trend that began with Pj, is a derived condition 
among otarioids, also seen in more advanced desmatophocids and odobenids (Mitchell 1975). 

7. Pj_4, single- rooted 

Further modification of the trend towards single-rooted cheekteeth occurs in the posterior premolars, 
P3_4; a feature long recognized as diagnostic of living fur seals and sea lions (Repenning and Tedford 
1977). 

8. M-' absent 

Since, as noted by Repenning and Tedford (1977), the absence of M^ in the holotype and only 
known referred specimen oi Pithanotaria starri may be the result of individual variation, its absence 
is tentatively regarded as a uniquely derived character for the monotypic genus. 

9. Mandibular foramen anteroventrally directed 

The anterior margin of the mandibular foramen is directed anterodorsally in Enaliarctos {this study), 
Thalassoleon mexicanus and Callorhinus. In the derived condition seen in Arctocephalus and sea 
lions this margin slopes anteroventrally (Fig. 3). 

10. Mandibular condyle elevated high above the base of the ascending ramus 

A high mandibular condyle is described and figured by Repenning, Peterson and Hubbs (1971:21; 
Fig. 7) as diagnostic of Arctocephalus australis. According to de Muizon (1978, Fig. 2) the derived 
condition is also seen in the fossil Hydrarctos lomasiensis and Otaria. 

11. Calcaneum with well-developed secondary shelf of sustentaculum 

All living otariids possess a well-developed secondary shelf of the sustentaculum (Robinette and 
Stains 1 970). This shelf is lacking in Enaliarctos (this study). As reported by Repenning and Tedford 
(1977), this shelf is also lacking in Thalassoleon mexicanus and only slightly developed in Hydrarctos 
lomasiensis (de Muizon 1978). 

12. Vertebral foramen enlarged 

Thalassoleon mexicanus is diagnosed as having vertebral foramina of all vertebrae small relative 
to those of living otariids (Repenning and Tedford 1977), but they are larger than in terrestrial 
carnivores. The derived condition, enlarged vertebral foramen, characterizes all other living otariids. 

13. Tibia and fibula fused proximally 

The unfused tibia and fibula of Callorhinus noted by Lyon (1937) is tentatively interpreted as 
retention of the primitive condition, seen in Enaliarctos (this study) and reported by Kellogg (1925) 
for Pithanotaria. ''Thalassoleon" macnallyae, in contrast to T. mexicanus, has a fibula fused proxi- 
mally to the head of the tibia (Repenning and Tedford 1977). In all other living otariids the tibia 
and fibula are likewise fused at their proximal ends. 

14. Basioccipital rectangular 

According to Repenning and Tedford (1977) the basioccipital is trapezoidal in Thalassoleon, Neo- 
phoca, and Zalophus. Our analysis indicates that Enaliarctos, Eumetopias and Otaria also share 



125 

the primitive condition. The shape of the basioccipital in Pithanotaria is equivocal, owing to 
incompleteness of this region of the skull in published specimens. In the derived condition, observed 
in all living fur seals and Phocarctos. this bone is rectangular with parallel lateral margins. 

15. P oval in cross section 

The size and shape of I' has been recognized as distinguishing fur seals from sea lions (Repenning 
et al. 1971). A large I' with a circular cross section typifies sea lions. Fossil otarioids including 
Enaliarctos. Thalassoleon and Pithanotaria share the primitive condition of an oval I' although 
they generally lack the large size of this tooth. 

16. Coronoid process narrow 

The coronoid process is very broad and overhanging along its posterior margin in Enaliarctos (this 
study) and Thalassoleon mexicanus (Repenning and Tedford, 1977). Arctocephalus has been dis- 
tinguished by Repenning, Peterson, and Hubbs (1971, Fig. 7) on the shape of the coronoid process. 
The presumably derived condition, a narrow process with posterior margin undercut and over- 
hanging at the base is found in A. gazella, A.forsteri, A. galapagoensis, A. philippii, A. australis and 
A. townsendi and Callorhinus. 

17. Reduced premaxillary 

The derived condition, defined as transverse width of premaxilla less than 40% of nasal length, 
especially apparent in lateral view, is an uniquely derived character for Callorhinus ursinus (Re- 
penning et al. 1971, this study). 

18. Lower cheek toothrow short 

This character is defined as the length of the cheek toothrow relative to the distance from P, to the 
ascending ramus. The derived condition, a short toothrow, is here defined as a toothrow less than 
75% of distance from P, to the ascending ramus (Fig. 4). 

19. M', single-rooted 

Among sea lions, M' is consistently single-rooted. Some variation was observed in fur seals, although 
in most species this tooth is double-rooted. The most variation recognized by Repenning et al. 
(197 1) was in Arctocephalus gazella, where approximately 50% of this sample exhibited the double- 
rooted condition. 

20. Accessory cusps on cheek teeth 

The presence of prominent, anterior and posterior accessory cusps on the cheek teeth is a derived 
character observed in several species of fur seal, Arctocephalus pusillus and A. australis (variable) 
and sea lions Neophoca, Otaria, and Phocarctos (Repenning and Tedford 1977, this study). 

2 1 . M'-^ positioned close together 

Since a "persistent diastema between M'-" is diagnostic of Thalassoleon (Repenning and Tedford 
1977), and was observed in Enaliarctos (Mitchell and Tedford 1973: fig. 5, Barnes 1979: fig. 20), 
the lack of a diastema is recognized as the derived condition. 

22. Facial angle less than 125° 

The facial angle is one of two characters identified by Repenning, Peterson, and Hubbs (1971 Fig. 
1 ) that consistently distinguishes Callorhinus from Arctocephalus and all other otariids. In the derived 
condition, seen in Callorhinus, the facial angle is less than 125°. 

23. Ectotympanic bone ornamented 

In the derived state, the medial border of the ectotympanic bone is ornamented, producing a flat, 
knobby bulla especially characteristic of male Callorhinus ursinus and ^"Thalassoleon'' macnallyae, 
unlike that of other species oi Arctocephalus (Repenning et al. 1971, Repenning and Tedford 1977). 
Among sea lions, Neophoca has an ornamented ectotympanic bone although the degree and position 
of the ornamentation differs from that of C ursinus. 

24. Pterygoid process of mandible with medial shelf 

Projection of the pterygoid process as a prominent medial shelf is recognized here as an autapo- 
morphy in Callorhinus ursinus. Zalophus shows a tendency to develop a shelf of smaller size and 
different proportion. 

25. Pterygoid process of mandible short and deep 

The shape of the pterygoid process was used by Repenning, Peterson, and Hubbs (1971 fig. 7) to 
distinguish Arctocephalus. In Thalassoleon mexicanus, the pterygoid process was described as similar 
to that o{ Arctocephalus pusillus in being long and shallow (Repenning and Tedford 1977) and the 
same is true for Enaliarctos (this study). The derived condition, a short, deep pterygoid process, is 
observed in Otaria in addition to A. galapagoensis, A. australis. A. forsteri, A. philippii, and A. 
townsendi. 

26. Nasals narrow 

The derived condition defined as nasal width 70% of nasal length was recognized in Arctocephalus 
philippii, A. tropicalis, Zalophus, Phocarctos and Otaria (Repenning et al. 1971: fig. 7, Sivertsen 
1954). 

27. Cheek toothrow straight 

In the primitive condition observed in fur seals, the cheek toothrow curves inward at P-' and 
diverges at M' creating a sinuous toothrow. In the derived condition, diagnostic of sea lions, the 
cheek toothrow is nearly straight (Fig. 5). In Otaria, Eumetopias and Phocarctos the derived state 
is slightly modified and the teeth converge at M'. 

28. Humerus stout, pectoral crest directed toward midpoint of distal articulation 

The derived condition of a robust humerus has been recognized as distinctive of sea lions. It has 
been suggested that the position of the pectoral crest resulted in a strengthening of the humerus, 
possibly related to their larger body size (Repenning and Tedford 1977). 



126 



29. Apex ofbaculum broad with keels 

The derived condition has been recognized as distinguishing sea hons from fur seals, which have a 
transversely narrow apex (Morejohn 1975). Thalassoleon and Callorhinus share a unique bacular 
morphology in which the bulbous ventral knob of the apex in anterior view resembles a "figure of 
eight" (Repenning and Tedford 1977). 

30. Apex of baculum further expanded laterally 

A further modification of the derived state discussed above, in which the lateral edges of the apex 
are expanded, is observed in Otaria, Neophoca, Eumetopias, and Phocarctos (see references cited 
above). 

31. Neopallium more convoluted 

The cerebrum of sea lions is characterized by more convolutions of the neopallium than that of fur 
seals (Repenning and Tedford 1977). More numerous neopallial convolutions are here interpreted 
as the derived condition based on the phylogeny established for fur seals and sea lions {see text). 

32. Postcruciate sulcus 

The postcruciate sulcus which connects the longitudinal fissure to the lateral sulcus appears to be a 
unique feature of Callorhinus. Presence of this sulcus in a juvenile endocranial cast of a skull referred 
to "Thalassoleon" macnallyae is here considered a shared derived feature linking these taxa (Re- 
penning and Tedford 1977). 

33. Posterior ectosylvian gyrus, narrow and unconvoluted 

Among fur seals, Callorhinus appears unique in having a noticeably narrow and unconvoluted 
posterior ectosylvian gyrus relative to the width of the adjacent posterior supersylvian gyrus (Re- 
penning and Tedford 1977). Presence of this derived feature in ''Thalassoleon" macnallyae is 
considered evidence of their close relationship. 

34. Frontal-Parietal suture in posterior position 

A posterior position of the frontal-parietal suture relative to the distance between the front of the 
braincase and the lambdoidal crest was observed in immature Callorhinus and "Thalassoleon" 
macnallyae as a feature distinguishing them from Thalassoleon mexicanus and Arctocephalus (Re- 
penning and Tedford 1977). 

35. Underfur sparse 

The sparse underfur of sea lions has long been used to distinguish them from fur seals (Scheffer 
1958). The presence of abundant underfur in fur seals has been considered retention of the primitive 
condition (Repenning and Tedford 1977). 

36. Underfur terminates at wrist 

Among fur seals, Callorhinus can be distinguished from Arctocephalus in having the fur of the 
forelimb terminate in an abrupt line at the wrist, whereas in Arctocephalus, the fur extends distally 
past the wrist (Repenning et al. 1971). Since the loss of abundant underfur is recognized as the 
derived condition (see character 35) its more restricted occurrence in Callorhinus is judged derived. 

37. Sucking louse host specificity 

The restricted occurrence of a more advanced sucking louse species, Antarctophirus microchir, on 
sea lions is interpreted as the derived condition. The presence of a more generalized taxon Proechi- 
nophthirus as a unique parasite on Callorhinus ursinus and Arctocephalus pusillus (and presumed, 
but not yet established on other species oi Arctocephalus), judged to be the primitive condition, has 
been interpreted as evidence for the greater antiquity of fur seals. The fact that different species of 
Proechinophthirus inhabit the two genera of fur seals indicates that they have evolved separately for 
some time (Kim et al. 1975). 

38. Strongly thigmotactic 

The tendency for sea lions and Arctocephalus pusillus to be strongly thigmotactic (limbs of different 
individuals in direct contact) while Callorhinus ursinus and other Arctocephalus species are not has 
been previously noted (Stirling and Wameke 1971 and references cited therein). Thigmotactic 
behavior is here interpreted as the derived condition based on the phylogeny established for fur 
seals and sea lions (see text). 

39. Palate deep and concave 

The sea lions Otaria, Neophoca and Phocarctos share the derived condition of having deep, concave 
palates (Scheffer 1958, King 1960). The palate is more highly arched in Phocarctos and Otaria than 
in Neophoca. In Phocarctos, the palate is deep anteriorly like that in Otaria however it is flattened 
posteriorly like that in Eumetopias and Neophoca (Mitchell 1968). 

40 Tympanic bulla with elongate posterior or posteroventral projection 

Phocarctos is characterized by having a "cylindrical projection of the bulla" (King 1960). As noted 
by Mitchell (1968) this projection is directed far posteroventrally in Otaria (where it is subequal in 
cross section) and posteriorly in Eumetopias (where it is more ovate in cross section). An elongate 
posterior or posteroventral projection of the tympanic bulla represents the derived condition. 

41. Cheekteeth 5/5 

Reduction in number of cheekteeth from 6/5 to 5/5 is a derived feature in Eumetopias and Neophoca. 
According to King (1983) the number is variable in Zalophus; Califomian animals more frequently 
having 5/5, Galapagos animals 6/5, while all variations are found in the Japanese animals. 



"^S y^ TRANSACTIONS 

OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 




Volume 21 Number 8 pp. 127-144 5 December 1986 



Fossil Tanaidacea 

Frederick R. Schram 

San Diego Natural History Museum. P.O. Box 1390, San Diego. CA 92112 USA 

u L. u J. /J 

Jiirgen Sieg 

Universitdt Osnahriick. 2848 Vechta. Federal Republic of Germany 

Eric Malzahn 

Aufder Heide 33, 3004 Isernhagen, Federal Republic of Germany 

Abstract. All known fossil tanaidaceans have been restudied and a taxonomic revision is provided. 
Some small alterations in the reconstruction of Anthracocaris scotica and Cryptocaris hootchi are made; 
Ophthalmapseudes rhenanus is reassigned to the Anthracocaridomorpha; O. friedericianus and O. 
acutirostris are placed in their own genus Jurapseudes. and O. giganteus (in part) is placed within its 
own genus Carlclausus. all within a new superfamily Jurapseudoidea within the suborder Apseudo- 
morpha; and O. giganteus (in part) is placed within another new genus, Cretitanais. within its own 
superfamily within the Tanaidomorpha. 

Introduction 

Tanaidaceans are among the most specialized of eumalacostracans. Morphologi- 
cally, ecologically, and behaviorally they have a modestly preserved, and in many 
respects intellectually satisfying, fossil record. They range from the Lower Carboniferous 
through the Cretaceous, and preserve a nice series from the extinct and very primitive 
to the extant and highly derived. Though the record is far from complete, we now know 
far more about the evolution of Tanaidacea than any other group within the brachy- 
caridan types. 

The oldest form known is Anthracocaris scotica (Peach) 1882, from the Lower 
Carboniferous of Scotland. Generic status was recognized by Caiman (1933), and a 
complete reconstruction and recognition as a tanaidacean was achieved by Schram 
(1979). Cryptocaris hootchi Schram, 1974 is from the Middle Pennsylvanian of Illinois. 
Ophthalmapseudes rhenanus (Malzahn) 1957, from the Permian of Germany, is the 
best preserved and most completely known of the Paleozoic forms; however, until now 
it was incorrectly placed among the apseudomorphs. 

The status of the Mesozoic tanaidaceans has heretofore been obscured by their 
mistaken placement, for the most part, all within a single genus, Ophthalmapseudes. 
The Triassic of Hungary contains a non-descript chela from Hungary designated as 
Ophthalmapseudes sp. by Vegh and Bachmayer. The Jurassic has much tanaid material. 
Malzahn (1965) described O. friedericianus, from the Middle Jurassic of Germany; 
Sachariewa-Kowatschewa and Bachmayer (1965) named O. acutirostris from the Mid- 
dle Jurassic of Bulgaria; and Reiff ( 1 936) named Palaeotanais quenstedti from the Lower 
Jurassic of Germany (although the types of this species are now lost). Cretaceous 
tanaidaceans are limited in number. Malzahn (1979) described a diverse array of 
specimens under a single species, O. giganteus, from the Lower Cretaceous of Germany. 

Over the years continued collection and preparation of specimens by one of us 
(EM) have resulted in much new material of various species of Ophthalmapseudes. 



128 



Analysis of these new specimens, combined with restudy of type material (FRS and 
JS), has allowed us to recognize that the tanaidacean fossils are much more diverse 
than previously suspected. This examination necessitates the complete revision of these 
fossils not only at the generic level, but also extending up to the superfamilial and 
subordinal levels. 

The synonymies of species are presented in the annotated format of Richter (1948) 
as outlined by Matthews (1973). Prefixes to numbers denote the following collections: 

EM — private collection of Eric Malzahn. 
EX— private collection of Dan Damrow. 
GSE— Institute of Geological Sciences, Edinburgh, Scotland. 
NMW — Natural History Museum, Vienna, Austria. 

P— Field Museum of Natural History, Chicago, USA. 
SDSNH— San Diego Society of Natural History, San Diego, USA. 

Z— Niedersachsisches Landesamt fiir Bodenforschung, Hannover, Germany. 

Systematic Paleontology 
Infraorder: Anthracocaridomorpha Sieg, 1980 

Diagnosis.— Eyes lobed. Thoracic pleurites present. Pereiopods cylindrical and 
stalk-like, exopods probably present on at least anterior 3 pereiopods. Abdomen with 
6 free pleomeres and telson, sixth pleomere larger than any of the first 5 pleomeres. 

Remarks. —Though the above characters are very descriptive of the Paleozoic 
tanaidaceans, in comparison to the living groups most of the characters could probably 
be considered primitive, which might indicate that this taxon is a paraphyletic one at 
best. Nonetheless, though we currently lack knowledge about possible derived features 
that the Paleozoic forms might share, these characters do consistently serve to separate 
the Paleozoic tanaidaceans from the Mesozoic and Cenozoic forms. 

Family Anthracocarididae Schram 1979 

Diagnosis.— Vropods multisegmented, uniramous. Telson either well developed 
or small. 

Type genus.— Anthracocaris Caiman, 1933. 

Remarks.— The uropods on specimens o^ Anthracocaris scotica appear to be uni- 
ramous, and except for the protopod are not preserved on Ophthalmapseudes rhenanus. 
However, we must point out that on modem tanaidaceans the exopod of the uropod 
is frequently greatly reduced. It is conceivable that this reduction might also be the 
case in the anthracocarids, with the vestigial uropodal exopods not being preserved or 
perhaps just not yet observed on the fossil material. 

The recognition of the anthracocaridomorph status of Ophthalmapseudes rhenanus 
and the inability to distinguish this taxon above the level of genus from Anthracocaris 
places the Ophthalmapseudidae Sieg, 1980, in synonymy with Anthracocarididae 
Schram, 1979. 

Genus Anthracocaris C3[m2Ln, 1933 
Figure 1 

Diagnosis.— Kosirum small. Telson long, subrectangular, terminally lobate (spat- 
ulate). Abdominal pleurites weakly developed and rounded, sixth pleomere vaulted 
and suboval in cross-section. 

Type species.— Palaeocaris scotica Peach, 1882. 

Gender. —Yemimne. 

Anthracocaris scotica (Peach), 1882 

V*. 1882 Palaeocaris scotica Peach, p. 85, pi. 10, figs. 10-lOb. 
1883 Palaeocaris scotica Peach. Peach, p. 515. 



129 




Figure 1. Reconstruction of Ant hracocaris scotica (Peach). (Modified from Schram 1979a.) 

1903 Palaeocaris scotica Peach. Peach and Home, p. 846. 

V. 1908 Palaeocaris scotica Peach. Peach, p. 154, pi. 8, figs. 1-5. 

1911 Palaeocaris scotica Peach. Woodward, p. 363. 

1933 Anthrococaris scotica (Peach). Caiman, p. 562, fig. 1. 

1962a Anthracocaris scotica (Peach). Brooks, p. 239. 

1962b Anthracocaris scotica (Peach). Hessler, p. R392, fig. 211, 1. 

1969a Anthracocaris scotia (Peach). Schram, p. 218, table 1. 

1974b Anthracocaris scotica (Peach). Schram, p. 107. 

V. 1979(2 Anthracocaris scotica (Peach). Schram, p. 100, figs. 46, 47, table 18. 

1979b Anthracocaris scotica (Peach). Schram, p. 164, table 1. 

1980 Anthracocaris scotica (Peach). Sieg, p. 406, figs. 2.1, 4. 

1981 Anthrocacaris scotica (Peach). Schram, p. 128, table 1, text-fig. 3. 

1983 Anthracocaris scotica (Peach). Sieg, p. 32, fig. 2. 

1984 Anthracocaris scotica (Peach). Sieg, pp. 34, 88, fig. 29. 

Lectotype.—GSE 5803; River Esk, Glencartholm, Dumfriesshire; Calciferous 
Sandstone Measures, Lower Carboniferous. 

Diagnosis. —SincQ there is presently only one species, the diagnosis is the same as 
that of the genus. 

Remarks.— To correct a lapse in Schram (1979), the lectotype was designated by 
Caiman ( 1 933), mistakenly termed at that time as a holotype. The reconstruction offered 
here (Fig. 1 ) is slightly modified from that in Schram ( \919a) to display more accurately 
the relationship of the chelipede to the carapace. 

Genus Ophthalmapseudes Glaessner (in Glaessner and Malzahn 1962) 

Diagnosis. —KosXruva prominent. Telson short, truncate, with a pair of large anal 
flaps. Abdominal pleurites well developed, projecting ventrolaterally as plate-like pro- 
cesses. Sixth pleomere incompletely vaulted, but posterolaterally flattened to form a 
shelf to which uropods articulate. 

Type species.— Macrura rhenana Malzahn, 1957. 

Gewt^^^T —Masculine. 

Ophthalmapseudes rhenanus (Malzahn), 1957 
Figures 2, 3 



V. 1957 Prosoponiscus problematicus Genitz. Malzahn; pi. 10, figs. 7, 8. 
';.* 1957 Macrura rhenana Malzahn, p. 104; PI. 10, figs. 9-11. 



130 




1 mm 




Figure 2. Reconstruction of Ophthalmapseudes rhenanus (Malzahn). Chelipedes in lateral view have been 
drawn more ventrad than they probably were in life to reveal more clearly the mandible and labrum. 



7955 Macrura rhenana Malzahn. Malzahn, p. 355. 

v. 1962 Ophthalmapseudes rhenanus (Malzahn). Glaessner in Glaessner and Malzahn, p. 259; fig. 4; pi. 2, 

figs. 6-13; pi. 3, figs. 1-13; pi. 4, figs. 1-22. 
7965 Ophthalmapseudes rhenanus (Malzahn). Malzahn, p. 228. 
7965 Ophthalmapseudes rhenanus (Malzahn). Sachariew-Kowatschewa & Bachmayer, p. 240; pi. 5, fig. 2. 

7965 Ophthalmapseudes rhenanus (Malzahn). Vegh and Bachmayer, p. 241; pi. 7, figs. 2, 3. 

7966 Ophthalmapseudes rhenanus (Malzahn). Forster, p. 34. 

1969 Ophthalmapseudes rhenanus (Malzahn). Hessler, p. R371; fig. 188-1. 

7969 Ophthalmapseudes rhenanus (Malzahn). Schram, p. 221, table 1. 

7970 Ophthalmapseudes rhenanus (Malzahn). Malzahn, p. 62. 
797-^ Ophthalmapseudes rhenanus (Malzahn). Schram, p. 104. 
7979 Ophthalmapseudes rhenanus (Malzahn). Malzahn, p. 74. 

1980 Ophthalmapseudes rhenanus (Malzahn). Sieg, p. 404, fig. 2H, fig. 4. 

Lectotype.—iyvQVQ designated) ZlOa; Borehole 57, Friedrich Heinrich Mine, near 
Kamp-Lintfort, Federal Republic of Germany; Zechstein 1 , Lower Permian. 

Paralectotypes.—ZlOh, ZlOc in the Landesamt, Hannover. 

Diagnosis. —Since there is presently only one species, the diagnosis is the same as 
that of the genus. 

Remarks.— A reexamination of all the original specimens, in addition to new 
material which has since become available, allows a detailed reconstruction of this 
species to be made for the first time (Fig. 2). We thus add to the otherwise excellent 
description of Glaessner (in Glaessner and Malzahn 1962) with these additional ob- 
servations. 

The distal portions of the antennules and antennae are still unknown, but the 
basalmost joint of the antenna is short and followed by a long joint that extends beyond 



131 




Figure 3. Ophthalmapseudes rhenanus (Malzahn). A) SDSNH 22255, dorsal view of anterior cephalotho- 
rax, X25.8; B) SDSNH 26257, ventral view of cephalon, x26.2; C) SDSNH 26256, left lateral view of 
cephalon, x39.0; D) SDSNH 26259, lateral view of thorax and abdomen, x27.3; E) SDSNH 26260, right 
lateral view of anterior thorax and cephalon, x 23.7; F) SDSNH 26258, ventral view of posterior thorax and 
abdomen, x24.4; G) SDSNH 26261, body terminus, x36.6. Antennule (a,), antenna (a^), anal plate (ap), 
basis of pereiopods (b), carapace (c), basis of chelipede (ch), dikonophor (dk), mandible (m), mandibular 
palp (mp), pleopod (pi), sixth pleomere (p^), pleomere pleura (pp), rostrum (r), third thoracomere (T,). 



132 




5 mm 



B 




Figure 4. Reconstruction of Cryptocaris hootchi Schram. (Modified from Schram 1974.) 



the tip of the rostrum (Fig. 3B). The mandibles are massive and seem to bear a palp 
near the base (Fig. 3C) that extends anteriorly to the labrum. The chelipede is 
composed of a short coxa, long basis (Fig. 3E), a short ischium, short merus, and a 
long carpus. The claw itself has a long and moderately deep propodus with a long finger, 
and a long dactylus. The form of the first pereiopod is still uncertain. The posterior 
pereiopods have short coxae and long cylindrical bases (Fig. 3D), and the carpus (at 
least on the anterior limbs) is equipped with stout spine-like setae. The posterior portion 
of the carapace is very much like that seen in modem forms with an opening into the 
branchiostegal chamber between the carapace rim and the chelipede (Fig. 3E). Males 
of this species are dikonophoric (Fig. 3F). The abdominal pleurites are well-developed 
and directed ventrad to protect the rather robust protopods of the pleopods (Fig. 3E). 
The small telson is terminally truncate with a pair of large anal flaps totally covering 
the posterior surface (Fig. 3G). The protopods of the uropods are small and cylindrical, 
and articulated with the posterolateral shelf of the sixth pleomeres. The distal rami of 
the uropods are not preserved on any of the specimens at hand. 

The equally developed ischium and merus on the chelipede represents a distinctly 
more primitive state than that seen in living forms, where the ischium and merus are 
either fused or the ischium is possibly reduced to a mere remnant (Gardiner 1975, 
Lauterbach 1970). Since this feature is not preserved on any of the known specimens 
of other anthracocaridomorphs, it is impossible at this time to comment on the sig- 
nificance of the equal and separate ischium and merus. However, if this character is 
consistent in the other Paleozoic species, it may be another diagnostic feature of the 
Anthracocaridomorpha. 



Ophthalmapseudes sp. (Vegh and Bachmayer, 1965) 

796^^ crustacean-like form, Vegh, p. 65. 

1965 Ophthalmapseudes sp., Vegh and Bachmayer, p. 241, pi. 7, figs. 4-6. 

1980 Ophthalmapseudes sp., Sieg, p. 406, fig. 4. 

Remarks. —ThtSQ rather nondescript portions of claw came from a borehole near 
Szentgal, Hungary, and are of Rhaetic, Triassic age. They have been compared to 
propodal and dactylar elements of O. rhenanus, but whether they actually are that 



133 




Figure 5. Cryptocahs hootchi Schram latex peel of EX 1882 showing the cephalon and anterior thorax, 
X 8.7. Anterolateral comer of carapace (ale), eye lobe (el), rostrum (r), third thoracomere (T,). 

species or not, or even in the genus Ophthalmapseudes, cannot definitely be determined 
without actual body specimens. It seems likely this matenal may eventually be deter- 
mined to be more akin to Jurapseudes {see below). 

Family Cryptocarididae Sieg, 1980 

Diagnosis.— XJropods biramous, rami 2-segmented and flap-like. Telson well de- 
veloped. 

Type genus. — Cryptocaris Schram, 1 974. 

Genus Cryptocaris Schram, 1974 
Figures 4, 5 

Diagnosis. —KosXwivn prominent. Cephalothorax with prominent anterolateral cor- 
ners, well-developed optic notch. Pereiomeres somewhat flattened, with paired longi- 
tudinal ridges on either side of dorsal midline, pleura well developed and extending 
laterad while each bears 3 longitudinal ridges. Abdominal pleura well developed. Telson 
moderate in length and rounded. 

Type species.— Cryptocaris hootchi Schram, 1974. 

G^«(^^r. —Feminine. 



Cryptocaris hootchi Schram, 1974 

v.* 1974 Cryptocaris hootchi Schram, p. 100, figs. 4-10. 
1976 Cryptocaris hootchi Schram. Schram, p. 26. 
1979a Cryptocaris hootchi Schram. Schram, p. 100. 
1979b Cryptocaris hootchi Schram. Schram, p. 164, table 1. 

1980 Cryptocaris hootchi Schram. Sieg, p. 406, figs. 2.1, 4. 

1981 Cryptocaris hootchi Schram. Schram, p. 128, table 1, text-fig. 3. 

1983 Cryptocaris hootchi Schram. Sieg, p. 232, fig. 2. 

1984 Cryptocaris hootchi Schram. Sieg, pp. 34, 88, fig. 29. 



134 



Holotype. — P32053; Peabody Coal Co. Pit 1 1, Will, Grundy, and Kankakee Coun- 
ties, Illinois, USA; Francis Creek Shale, Carbondale Fm., Desmoinsian, Upper Penn- 
sylvanian (Westphalian D). 

Diagnosis. — Since there is presently only one species, the diagnosis is the same 
as that of the genus. 

Remarks.— K detailed description is to be found in Schram (1974). However, 
reexamination of available material in light of more complete understanding of the 
other Paleozoic tanaidaceans requires some adjustments in the diagnosis and recon- 
struction (Fig. 4). The thoracic pleura are directed laterad (Fig. 5), and the anterolateral 
comers of the carapace are prominent. 

In regards to this latter feature there are two interpretations. One of us (JS) feels 
these comers may represent a condition like that seen in many living tanaidaceans, 
where the lobed eyes become fused with the antero-lateral region of the cephalothorax. 
However, another of us (FRS) feels there is some evidence on the fossils that suggest 
separate eye lobes (mistakenly referred to and reconstructed as stalked eyes in Schram, 
1974) associated with the optic notches (Fig. 5). The issue can only be resolved with 
the discovery of better preserved material of this species. 

Infraorder: Apseudomorpha Sieg, 1980 

Diagnosis. —Body more or less dorsoventrally flattened. Eyes primitively lobed or 
fused to cephalothorax. Pereion with tendency for first pereiomere to fuse with ceph- 
alothorax, males with one or two genital cones, without thoracic glands. Pleon with 5 
free pleomeres and a pleotelson. Sexual dimorphism weakly developed, only affecting 
antennae and chelipedes. 

Superfamily Jurapseudoidea nov. 

Diagnosis.— Body slightly dorsoventrally flattened. Males dikonophoric, with strong 
chelipedes. 

Family Jurapseudidae nov. 

Diagnosis.— Since only one family is presently recognized, the diagnosis is the 
same as that of the superfamily. 

Type genus. —Jurapseudes gen. nov. 

Genus Jurapseudes nov. 

Diagnosis. — Pleon with free pleomeres short, pleurites developed as ventrolaterally 
directed processes, stemites undecorated. Pleotelson long, highly vaulted, laterally de- 
veloped with flange or ridge. 

Type species. — Ophthalmapseudes friedericianus Malzahn, 1965. 

Gender. — Masculine. 

Etymology.— ¥or Jurassic, and the resemblance to living apseudomorphs. 

Remarks. —The pleotelson of this genus (Fig. 6 A) greatly resembles that distinctive 
pleotelson of the modem genus Discapseudes (Bacescu and Gutu 1975). 

Jurapseudes friedericianus (Malzahn) 1965 
Figures 6A, B, and 7 

v.* 1965 Ophthalmapseudes friedericianus Malzahn; p. 223; Pis. 1-4. 

7965 Ophthalmapseudes friedericianus Malzahn. Sachariewa-Kowatschewa & Bachmayer; p. 238; pi. 5, fig. 4. 

1966 Ophthalmapseudes friedericianus Malzahn. Forster, p. 33. 

V. 1970 Ophthalmapseudes friedericianus Malzahn. Malzahn, p. 64; pi. 1, figs. 1-7; pi. 2. 

7979 Ophthalmapsuedes friedericianus Malzahn. Malzahn, p. 74. 

7950 Ophthalmapseudes friedericianus Malzahn. Sieg, p. 406, fig. 4. 

Holotype. —NM'W 632/1965/1; Level 13, Friedericke Mine, near Bundheim/Bad 
Harzburg, Federal Republic of Germany; alpha Dogger, Lineatum Zone, Middle Ju- 
rassic. 



135 




C 
2 mm 




A 



1 mm 




D 



D 



1 mm 



1 mm 



Figure 6. Reconstructions of fossil Apseudomorpha. A & B) Jurapseudes friedericianus (Malzahn), A) 
dorsal body, B) large male chela, and two variant female chelae, C) J. acutirostris (Sachariewa-Kowatschewa 
and Bachmayer), D & E) Carlclausus emersoni n. gen., n. sp., D) dorsal body without anterior part of 
cephalon, E) chela with two variant daclyli opposed to the massive propodus. 



136 






Figure 7. Jurapseudes friedericianus (Malzahn). A) EM 1, carapace with left anterior portion broken away, 
x37; B) SDSNH 26253, ventral view of abdomen, x 17.5; C) SDSNH 26254, pleotelson, x24.3. Rostrum 
(r), optic notch (on), broken hyposphanium (h), places of pleopod attachment (p). 



Paratypes.—l<iyV^ 632/1965/2-27, from type locality. 

Additional specimens. -EM 1-8 (illustrated in Malzahn 1970) SDSNH 26251- 
26254; Lower Bathonian, near Hildesheim (Malzahn 1970), Lower Saxony, Federal 
Republic of Germany. 

Diagnosis, —^ody small (cephalothorax ~2 mm). Rostrum broad. Cephalothorax 
relatively longer than wide (length/width ratio 1:0.9). First 2 periomeres almost as long 
as wide (length/width ratio 1:1.8). 

Remarks. —The presence of a pleotelson (Fig. 7C) clearly separates this genus from 
the Permian anthracocaridomorph Ophthalmapseudes, whereas the slightly flattened 
body form, completely segmented pleon, and long pleotelson most closely ally these 
Jurassic forms to the modem apseudomorphs. 

Malzahn originally characterized males of the species as having one or possibly 
two genital cones. However, the single specimen which seemed to suggest a monoko- 
nophoric condition (Malzahn 1965, plate II, fig. 4) appears to have (Fig. 7B) a broken 
hyposphanium (=midventral process of the stemite). The species thus is probably 
dikonophoric. 

We have also noted three distinctly different forms of claw (Fig. 6B). One obviously 
belongs to a male in which the dactylus is thin and widely separated from the propodal 
finger; the entire claw is larger on the whole than either of the other forms. The other 
two morphs are smaller and probably belong to females; they are distinguished on the 
basis of whether there is one or two teeth on the inner margin of the dactylus and on 
the relative length of the dactylus. These two "female" morphs could represent variants 
between copulatory and precopulatory phases. 

Earlier illustrations of the carapace of this species (Malzahn 1970: table 1, fig. la) 
were not particularly clear. That specimen is re-illustrated here (Fig. 7A). 



Jurapseudes acutirostris (Sachariewa-Kowatschewa and Bachmayer) 1965 

Figure 6C 

v.* 1965 Ophthalmapseudes acutirostris, Sachariewa-Kowatschewa and Bachmayer; p. 238; pi. 5, fig. 3; pi. 4. 
1966 Ophthalmapseudes acutirostris, Sachariewa-Kowatschewa and Bachmayer. Forster, p. 34. 



137 

1980 Ophthalmapseudes acutirostris. Sachariewa-Kowatschewa and Bachmayer. Sieg; p. 406, figs. 2.2F, G, 
and 4. 

//o/ory/7£'. -(by monotypy) NMW 633/1 96 5/C 10; Borehole Nikola Koslewo, depth 
751.6 m, northern Bulgaria; Dogger, Middle Jurassic. 

Diagnosis.— Body moderate in size (cephalothorax length ^6 mm). Rostrum nar- 
row, terminally pointed. Cephalothorax relatively shorter than wide (length/width ratio 
1:1.1). First 2 pereiomeres much shorter than wide (length/width ratio 1:3). 

Remarks.— The diagnostic characters of the genus Jurapseudes involve the pos- 
terior end of the body. However, the resemblance of 7. acutirostris to the known anterior 
portions of J. friedericiamis is so close that there seems little doubt that these species 
should be retained in the same genus, at least until information to the contrary becomes 
available. 

Forster (1966) compared a single Lower Dogger tanaidacean fossil to O.friederi- 
cianus. That specimen, from borehole Reichertshausen 1 from the Brigitta Mine in 
southern Germany at a depth of 1343.9 m, consists of a pereion and portions of the 
anterior pleomeres. 

Carlclausus gen. nov. 

Diagnosis. -VXeornQves highly vaulted; with well-developed, laterally directed pleu- 
ral processes; stemites with prominent, tubercular hyposphaenia. Pleotelson long, highly 
vaulted, developed posterolaterally as a flange or ridge. 

Type species. — Carlclausus emersoni sp. nov. 

G^«<^^r. —Masculine. 

Ervmc/ogT.— Named after the pioneer tanaidacean worker Carl Claus. 

Carlclausus emersoni sp. nov. 
Figures 6D, 8 

vp.* 1979 Ophthalmapseudes giganteus (partim) Malzahn; p. 780; pi. 1, figs. 6-9; pi. 2, figs. 3-18; pi. 3. 

Holotype. —NMW 1985/44/1 (Fig. 8E); Engelbostel Brickyard claypit, west of the 
Flughafen Langenhagen highway in Hanover, Federal Republic of Germany; Lower 
Hauterivian, high in Endemoceras amblygonium Series, Lower Cretaceous. 

Paratypes. —NMW 1985/44/2-1 1, same locality as holotype. 

Etymology. —Named in honor of Michael J. Emerson, whose powers of observation 
and contributions to this project both scientifically as well as artistically resulted in a 
far better paper than what might have been. 

Diagnosis.— Since only one species is presently recognized, the diagnosis is the 
same as that of the genus. 

Description. —The anterior pereiomeres have rounded pleura (Fig. 8 A). The pos- 
terior pereiomeres seem to be developed with pointed, laterally directed processes (Fig. 
8B). The pereiomere stemites have hyposphaenia, and the males are apparently dikon- 
ophoric (Fig. 8B). The 5 free pleomeres have large, laterally directed pleural processes 
(Fig. 8C, D) which arise slightly anteriad of the pleopod articulations. These processes 
arc posteriad as they extend laterally away from the body. The articular areas of the 
pleopods are quite large, and between any one pair of them, on the midline of the 
stemite, is a prominent hyposphaenium, the distal tips frequently being broken (Fig. 
8D). The highly vaulted telson is wider distally than proximally because of the pos- 
terolateral flange or ridge to which the uropods articulate (Fig. 8E). 

Malzahn (1979: plate 3) illustrated a variety of chelae. These seem to be of two 
kinds (Fig. 6E). One is a long thin form with a single small tooth near the base; the 
other is a shorter, more massive form with a large tooth arising at the base. These are 
opposed to a massive protopod with two teeth on the finger. 



138 








Figure 8. Carlclausus emersoni n. gen., n. sp. A) NMW 1985/44/2, posterior portion of carapace and two 
anteriormost pereiomeres, xl8.5; B) NMW 1985/44/3, ventral view of last two pereiomers and first two 
pleomeres, hyposphanum (h), dikonophore (dk), x24.3; C) NMW 1985/44/4, dorsal view of pleon, with 
bases of laterally directed pleura, x 28.6; D) NMW 1985/44/5, ventral view of portion of pleon, with laterally 
directed pleura, x26.6; place of pleopod attachment (p), hyposphaena (h); E) NMW 1985/44/1, holotype, 
pleotelson showing diagnostic posteriorly flaring lateral ridges, x 37.5. 



Remarks.— MosX of the material used in Malzahn's (1979) supplemental descrip- 
tion of Ophthalmapseudes giganteus, noted by him as exceptions to the holotype of 
that species, is assignable to this entirely separate genus and species, C emersoni. This 
new species has only the most distant taxonomic affinities to the former. Rather, 
Carclausus seems to bear some relationship to the Jurassic jurapseudids, based on the 
possession of a long pleotelson with some development of lateral flanges or ridges, and 
the prominent laterally directed pleural processes on the pleomeres. 



139 

Jurapseudoidea incerta sedis 
Palaeotanais quenstedi Reiff, 1936 

1885 Isopodites sp. Quenstedt, p. 423, fig. 14. 

1936 Palaeotanais quenstedti Reiff, p. 86, figs. 17, 18. 

7962 Palaeotanais quenstedti Reiff. Glaessner and Malzahn, p. 262. 

1965 Palaeotanais quenstedti Reiff. Bachmeyer et al., p. 221. 

1966 Isopodites Forster, p. 33. 

1966 Palaeotanais quenstedti Reiff. Forster, p. 34. 

1969 Palaeotanais quenstedti Reiff. Hessler, p. R371, fig. 188-2. 

7970 Palaeotanais quenstedti Reiff. Malzahn, p. 61. 

7979 Palaeotanais quenstedti Reiff. Malzahn, p. 68. 

1980 Palaeotanais quenstedti Reiff. Sieg, p. 406, figs. 2.2E, 4. 

Holotype. —lost; Dueraau near Boll, Federal Republic of Germany; Liassic, Lower 
Jurassic; originally deposited in the collections of the Geological Institute, Tiibingen. 

Remarks.— \3nXW the holotype is found and additional material is collected from 
the Liassic, the affinities of this fossil must remain uncertain. Its placement here among 
the apseudomorphs is a matter of interpretation from the literature. Although no 
diagnostic features were preserved on the type specimen, none of the recorded infor- 
mation on this species excludes it from possible apseudomorph assignment. 

Superfamily Apseudoidea Leach, 1814 

Diagnosis.— Body strongly flattened dorsoventrally. Eyes fused to cephalothorax. 
Males monokonophoric. Uropods biramous and multisegmented. 

Remarks.— \n light of our better understanding of fossil forms, some slight mod- 
ification of the diagnosis of this superfamily is necessary in regards to the fused condition 
of the eyes. No fossils of this superfamily are known. 

Infraorder Tanaidomorpha Sieg, 1980 

Diagnosis.— Body more or less cylindrical. Mandible without palp, maxillule with 
only a single endite and palp, maxilla greatly reduced. First pereionite without tendency 
to fuse to cephalothorax. Males mono- or dikonophoric. Pleon with tendency to fuse 
segments, pleotelson small. Sexual dimorphism may be strongly developed; involving 
antennae, chelipedes, mouthparts, and body shape. 

Remarks.— ThQVQ are no fossils currently known that can be assigned to the 
superfamilies Tanaoidea and Paratanaoidea. The single fossil tanaidomorph recognized 
here possesses such an array of distinctively primitive features that it requires its own 
superfamily. 

Superfamily Cretitanaoidea nov. 

Diagnosis.— knXtrior pereiomeres developed with small pleurites. Pleon with 5 
free segments, pleotelson small. 

Family Cretitanaidae nov. 

Diagnosis. —SincQ only one family is presently known, the diagnosis is the same 
as that of the superfamily. 

Type genus. — C ret it anais gen. nov. 
Genc^^r. —Masculine. 

Genus Cretitanais nov. 

Diagnosis.— Body large. Branchiostegal portion of carapace separated from dorsal 
field of cephalothorax by longitudinal furrow. First 5 pereiomeres subequal, sixth pe- 
reiomere distinctly shorter than anterior segments. Pleotelson short, apparently broadly 
rounded. 

Type species. —Ophthalmapseudes giganteus Malzahn, 1979. 

Gender.— y\.diSC\x\\nQ. 



140 




5 mm 




Figure 9. Reconstruction of Cretitanais giganteus (Malzahn). 



Cretitanais giganteus (Malzahn) 1979 
Figures 9, 10 

v.* 1979 Ophthalmapseudes giganteus Malzahn, p. 67; pi. 1, figs. 1-5; pi. 2, figs. 1, 2. 

1979 Apseudes giganteus Malzahn, p. 67. 

1982 Apseudes giganteus (Malzahn). Malzahn and Pockrandt, p. 57. 

Holotype. — NMW 1978/1997/1; Engelbostel Brickyard claypit, west of the Flugha- 
fen Langenhagen highway in Hannover, Federal Republic of Germany; Lower Hau- 
terivian, high in the Endemoceras amblygonium Series, Lower Cretaceous. 

Diagnosis.— Since, only one species is presently recognized, the diagnosis is the 
same as that of the genus. 

Remarks. —Though Malzahn (1979) confused specimens of what we now recognize 
as two different species, he carefully separated the diagnosis of the taxon and the 
description of the holotype specimen from the "additional examples" (now assigned 
to a new taxon, Carlclausus emersoni). The pertinent features of the type specimen 
which allow placement of Cretitanais giganteus within the Tanaidomorpha are as 
follows: 1) the posterior of the carapace (Fig. 10 A, B) is inflated and complete (not 
deeply excavated as is generally the case in the neotanaidomorphs); and 2) the sixth 
pereiomere (Fig. IOC, D) is much shorter than that of the fifth or anterior segments, 
and bears well-developed pereiopods. The pereiopods are apparently cylindrical or 
stalk-like (Fig. IOC), not fossorial or flattened. This condition of the legs is generally 
considered a primitive feature and more characteristic of tanaidomorphs, while neo- 
tanaidomorphs exhibit tendencies toward fossorial type legs. 

Non-tanaidacean fossils 
Apseudes sp. (Malzahn and Pockrandt, 1982) 

Remarks. —This specimen, NMW 1979/2057, is not a tanaid, but rather a portion 
of a decapod abdomen. The published figures (Malzahn and Pockrandt 1982, plate 1, 
especially figs. 5, 6) have the matrix and part of the fossil whitened out, thus mistakenly 
highlighting non-existent tanaidacean features. 



14: 






Figure 10. Cretitanais giganteus (Malzahn), holotype, NMW 1978/1997/1. A) left side of cephalon, x 9.6; 
B) right side of cephalon, with chelipede, basis (b), possible ischium (?i), merus (m), carpus (c), propodus 
(p), X 10.8; C) left view of posterior pereion and abdomen, pereiomeres (5, 6), pleomeres (1-5), pleotelson 
(pt), a posterior pereiopod extending below b, x6.9; D) dorsal view of C, x 7.9. 

Charassocarcinus mayalis (Eudes-Deslongchamps) 1878 

Remarks. —This species was arbitrarily assigned by Glaessner (1969:R628) to the 
tanaidaceans. The type and only known specimen has long been lost, but from ex- 
amination of descriptions and illustrations of this form in comparison to known fossil 
and recent tanaidaceans we feel confident in returning this problematic form— as a 
nomen dubium — to the ranks of the Decapoda. 



Discussion 

Although the Tanaidacea are now perceived to have a remarkably good fossil 
record, all things considered, our knowledge is still not comprehensive enough to be 
able to present an unequivocal cladogram of relationships. Classic cladislic analysis 



142 



would require defining lists of symplesiomorphies and synapomorphies. Unfortunately, 
our ignorance of the fine details of fossil appendage morphology, especially mouthparts, 
allows us to deal only with gross changes in body plan. So while we might conceptualize 
the main steps in tanaidacean evolution with the use of the fossils discussed here, we 
still lack the knowledge to analyze the small phylogenetic steps, as is possible with 
living forms (see e.g., Sieg 1983, 1984). These latter naturally would have been the 
basis for the changes in gross body morphology. 

Little more can be added to the hypothetical "urtanaidacean" recently proposed 
by Sieg (1984). Corrections presented here in the reconstruction of Cryptocaris hootchi 
Schram, 1974, would seem to verify that the body shape of the archaic tanaidaceans 
was more or less dorsoventrally flattened. This perception agrees with current under- 
standing of the morphological changes that occurred when the neotanaidomorphs and 
tanaidomorphs developed (Sieg 1983, 1984). Furthermore, the ancestral tanaidacean 
type fused the first 2 thoracomeres with the cephalon, transformed the second thora- 
copod into a chelipede, and possessed an abdomen of 6 pleomeres and a free telson. 
Equally it is noteworthy that the sixth pleomere is nearly always much longer than any 
of those preceding it. We might also expect the basal tanaidacean stock to have possessed 
a tailfan with broad uropodal rami, similar to that of Cryptocaris. 

Indeed, with its extensive array of primitive features, Cryptocaris could be con- 
sidered as the sister group to all other tanaidaceans. Unfortunately, we currently lack 
any apomorphies that would unambiguously diagnose the Cryptocarididae as mono- 
phyletic in relation to the Anthracocarididae. However, because Cryptocaris is younger 
than the more advanced Anthracocaris, we can anticipate future fossil discoveries in 
the late Paleozoic that will allow us to clarify the relationships among these archaic 
forms. Presently, we would hypothesize that in the Lower Carboniferous there were 
probably 2 distinct evolutionary lineages. One (represented by Cryptocaris) was basi- 
cally a derivation of the ancestral stock, the other (represented by Anthracocaris and 
Ophthalmapseudes) was convergent in form, if it did not directly lead, to the recent 
tanaidaceans. By the beginning of the Mesozoic the fusion of the sixth pleomere and 
telson occurred, since all Mesozoic and Recent forms possess a pleotelson. 

Anthracocaridomorpha, as currently understood, is a paraphyletic taxon because 
it can only be characterized by primitive features. However, since at this time we cannot 
define adequately the monophyletic status of either of the cryptocarids or anthracocarids 
we feel justified in placing these families within a single suborder. 

The fossils described here suggest a solution to a minor problem related to deter- 
mining the number and identity of chelipede joints. It was formerly thought that within 
the apseudomorphs the ischium was totally reduced, whereas there was still a small 
remnant in the neotanaidomorphs (Gardiner 1975). It was thought that tanaidomorphs 
also originally possessed an ischium. Lauterbach (1970) observed a small chitinous 
bracelet on Tanais cavolinii (=T. dulongii), but this structure can be interpreted as 
either an ischium or as a rudiment of the dorsal portion of the merus (Sieg 1983Z)). 
The well-developed ischium and merus in Ophthalmapseudes rhenanus (Fig. 2) would 
seem, to at least one of us (JS), to support the idea that the apseudomorph "merus" is 
in reality an ischio-merus, and that tanaidomorphs might possess only a merus. This 
would perhaps serve to explain the relative size of the large aspseudomorph "merus" 
in comparison to the more diminutive joint seen in the neotanaidomorph/tanaido- 
morph line. However, it is unclear (FRS) whether Cretitanais giganteus may preserve 
a remnant of a small ischium on what appear to be its chelipedes (Fig. 1 OB). 

The radiation of the modem Tanaidacea must have taken place in the Mesozoic. 
With little doubt the Jurassic Jurapseudes belongs within the apseudomorphs, and the 
same conclusion can be drawn for the Cretaceous Carlclausus. On the other hand 
Cretitanais would seem best placed within the tanaidomorphs. Though fossils assignable 
to Recent tanaidacean families and/or superfamilies are lacking, the record implies that 
the evolution of the apseudoidean and tanaidomorph families probably took place by 
late Mesozoic time (Late Cretaceous). Unfortunately, as is the case among the Paleozoic 
taxa, our current knowledge of the Mesozoic tanaidaceans does not allow us to char- 



143 



acterize unambiguously with apomorphic features the jurapseudoids and cretitanaoids. 
However, we are reasonably confident that future fossil discoveries will support our 
hypothesized phyletic relationships within the known fossil and Recent Tanaidacea. 

Acknowledgments 

We would like to extend special thanks to Michael J. Emerson who assisted in 
preparing the fossils and who produced the figures, and to Marjorie Rea who typed the 
text. Research was supported in part by NSF grants DEB 79-03602 and BSR 82-12335 
to FRS and by grants from the Deutsche Forschungsgemeinschaft to JS. 



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Richter, R. 1948. Einfiihrung in der Zoologische 
Nomenklatur 2nd ed. Kramer, Frankfurt. 

Sachariewa-Kowatschewa. K., and F. Bachmayer. 
1965. Fine neue fossile Scherenassel 
(Ophthalmapseudes acutirostris) aus den Dog- 
ger-Schichten von Bulgarien. Annalen des Na- 
turhistorischen Museum in Wien 68:236-240. 

Schram, F. R. 1969. Stratigraphic distribution of 
the Paleozoic Eumalacostraca. Fieldiana: Ge- 
ology 12:213-234. 

. 1974. Late Paleozoic Peracarida of North 

America. Fieldiana: Geology 33:95-124. 

. 1976. Some notes on Pennsylvanian crus- 
taceans of the Illinois basin. Fieldiana: Geology 
35:21-28. 

. 1979a. British Carboniferous Malacos- 

traca. Fieldiana: Geology 40:1-129. 

. 1979/7. The Mazon Creek biotas in the 

context of a Carboniferous found continuum. 
Pp. 159-190 m M. H. Nitecki (ed.). Mazon 
Creek Fossils. Academic Press, New York. 

. 1981. Late Paleozoic crustacean com- 
munities. Journal of Paleontology 55: 1 26-1 37. 

. 1982. The fossil record and evolution of 

Crustacea. Pp. 93-147 in L. G. Abele(ed.). The 



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Biology of Crustacea, Vol. 1. Academic Press, 
New York. 

Sieg, J. 1980. Sind die Dikonophora eine poly- 
phyletische Gruppe? Zoologische Anzeiger 205: 
401-416. 

. 1983. Evolution of Tanaidacea. Crusta- 
cean Issues 1:229-256. 

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lichen System der Tanaidacea, eine phyloge- 
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— , and F. Bachmeyer. 1965. Fossile Sche- 



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Woodward, H. 1911. On a large form of /l«?/zra- 
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Rochdale. Geological Magazine (5)8:361-366. 



TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 




Volume 21 Number 9 pp. 145-153 5 December 1986 



Another new forest-dwelling frog (Leptodactylidae: Eleutherodactylus) 
from the Cockpit Country of Jamaica 

DEC 

Ronald I. Crombie 

Department of Vertebrate Zoology, National Museum of Natural History. Smithsonian Institution, Wash- 
ington D.C. 20560 USA 

Abstract. A new, diminutive species of Eleutherodactylus is described from the mesic forests of 
the Cockpit Country, Trelawny Parish, west-central Jamaica. The new species is placed in the gossei 
group (sensu Crombie 1977) and is distinguished from other members of this assemblage by its small 
size, bright yellow belly in life, smooth dorsum, and a variety of other morphological characters. The 
species is compared with similar Jamaican congeners and data are presented on its natural history, 
variation, and possible relationships. 

Introduction 

In 1938 the late George S. Myers commented that, ". . . it would seem that one 
of the chief diversions of contemporary American herpetologists is the describing of 
new West Indian Eleutherodactyli! If I am not believed, I would refer my questioner 
to Dr. Barbour's recent list (1935)" (Myers 1938:355). Barbour listed 60 species of 
Eleutherodactylus in his 1935 West Indian checklist. Forty years later, despite the 
synonymization of several of the taxa Barbour mentioned, the total had more than 
doubled (Schwartz and Thomas 1975, Schwartz et al. 1978). With apologies to Dr. 
Myers, I herein contribute another, albeit quite distinctive, new species from Jamaica. 
I also suggest that the situation in South America, where nearly 1 00 new species have 
been described since 1968 (27 in 1980 alone), would have horrified Dr. Myers even 
more. 

In the past twelve years of field work in the Cockpit Country of west-central 
Jamaica, I have been fortunate to catch a glimpse of what much of the West Indian 
wet forests must have been like before the arrival of humans. The brutal, unforgiving 
terrain of the Cockpits has largely prevented the wholesale habitat destruction that has 
modified the distribution and abundance of many Jamaican animals. The result is a 
unique pocket of relatively undisturbed forest that supports a number of endemic taxa 
and acts as a refuge for species that could not adapt to the cane fields, rolling pasture, 
and patchy scrub forest that now characterize much of the island. Sadly, even the 
Cockpits have recently been under considerable pressure to accommodate the bur- 
geoning population of Jamaica, and modification of the forests has intensified in the 
past five years. 

In describing Eleutherodactylus sisyphodemus from the deep forests of the Cockpits 
(Crombie 1977), I compared the new taxon with an equally small, yellow-bellied, 
syntopic species that I believed was E. luteolus (Gosse). Additional field work and an 
examination of Coin's (1953) material at the Carnegie Museum revealed that E. luteolus 
and the yellow-bellied frog were not conspecific. 

As pointed out by Schwartz and Fowler ( 1 973: 1 22-1 24), Eleutherodactylus luteolus 
is a small to medium-sized species (males to 17.3 mm SVL, females to 25.8 mm SVL) 
that usually lacks bright ventral or inguinal coloration, has a prominent dark facial 
mask, and has distinct supra-axillary and inguinal glands; the latter character Goin 



146 



(1953) neglected to mention in his redescription of the species. Eleutherodactylus lu- 
teolus is found in a variety of open, disturbed habitats, including pastures, roadsides 
and even beaches (Goin 1953, Crombie, personal observation). Prior to 1977 I had 
collected only a few E. luteolus in such habitats in Hanover Parish and, on casual 
examination, considered them identical to the yellow-bellied Cockpit frog, despite the 
great discrepancy in habitat. In 1978, I collected specimens of a moderate-sized, drab 
frog with prominent supra-axillary and inguinal glands from road cuts, rock walls and 
in gardens near the town of Quick Step on the southern edge of the Cockpits. I tentatively 
regarded them as a new species since they differed so strikingly from similarly sized 
Jamaican Eleutherodactylus. However, in examining Coin's material of E. luteolus at 
the Carnegie Museum, I found that females were very much larger and stockier than 
males and that even poorly preserved specimens had indications of glands. Reexam- 
ination of my specimens from the Quick Step road revealed that they were indeed large 
female E. luteolus and that the yellow-bellied species from the forest was distinct and 
undescribed. References to Eleutherodactylus luteolus in my 1977 paper refer to the 
new species. 

Eleutherodactylus griphus, sp. nov. 

Holotype. —National Museum of Natural History (USNM) 250000, a gravid female 
from the vicinity of "the cave," about 7 mi (11.2 km) WNW Quick Step, Trelawny 
Parish, Jamaica, ca. 250 m elevation, collected by L. Richard Franz and R. I. Crombie 
on 8 April 1978. 

Paratopotypes (59).— USNM 250033-48, same data as holotype; San Diego Society 
of Natural History (SDSNH) 64197-99, 64201, USNM 244472-73, collected by Greg- 
ory K. Pregill, R. I. Crombie and Linda K. Gordon on 1 1 June 1983; USNM 244469- 
71, collected by G. K. Pregill, R. I. Crombie and L. K. Gordon on 10 June 1983; 
USNM 250005-1 1, Carnegie Museum of Natural History (CM) 1 12377-78, Museum 
of Comparative Zoology, Harvard University (MCZ) 107864-65, Albert Schwartz Field 
Series (ASFS) V3 6 3 84-8 5, collected by R. I. Crombie, Jeremy F. Jacobs and Barbara 
A. Harvey on 12 July 1975; USNM 250012-32, collected by R. I. Crombie, Frances 
I. McCullough, J. F. Jacobs and Menocal Stephenson on 15 July 1977. 

Additional paratypes (4).-USNM 250001-04, from 0.5-1.0 mi (0.8-1.6 km) N 
of Quick Step, ca. 350 m, Trelawny Parish, Jamaica, collected by R. I. Crombie, F. I. 
McCullough, J. F. Jacobs and M. Stephenson on 14 July 1977. 

Referred specimens.— \5S^M 244607 (dry skeleton) collected at the type locality 
by G. K. Pregill, L. K. Gordon, William B. Hilgartner and Richard Thomas, 1 6 June 
1983; USNM 244627 (cleared and stained), same locality, collected by G. K. Pregill, 
L. K. Gordon and R. I. Crombie on 1 1 June 1983. 

Diagnosis. —A small species (males to 1 4.2, females to 1 8.4 mm SVL) distinguished 
from all other Jamaican Eleutherodactylus by the following combination of characters: 
prominent dark canthal bars or facial mask and dark lateral stripes extending to near 
midbody, belly metallic yellow in life with no red or orange in groin or on concealed 
parts of legs, throat with distinct dark spots or extensive marbling, smooth dorsal skin 
with no scapular "W," no inguinal or supra-axillary glands, no tarsal fringe or calcar, 
no toe webbing. 

Description of holotype.— A gravid female with the following measurements (in 
mm): snout vent length (SVL) 16.4; head length (HL) 6.9; head width (HW) 6.9; 
tympanum diameter (TYM) 1.0; eye diameter (EYE) 2.6; naris-eye distance (NE) 1.9; 
femur length (FEM) 8.5; tibia length (TIB) 8.0; foot length (FT) 8.0. Head as long as 
broad; HW/SVL 42%. Snout rounded in dorsal and lateral view, canthus rostralis 
rounded; loreal region obtuse; lips not flared. Nostrils lateral, much closer to tip of 
snout than eye; eye diameter greater than distance from naris to eye, interorbital distance 
2.2, less than eye diameter. A single indistinct tubercle on each upper eyelid. Tympanum 
distinct, round, proportionally larger in males. Tongue lanceolate, slightly nicked be- 
hind, free posteriorly for more than half its length. Choanae moderate-sized, elliptical; 
prevomerine dentigerous processes in two long, arched series from level of outer choanal 



147 



border, almost meeting on palatal midline; separated by a distance of less than Haifa 
choanal diameter. Fingers moderately long, unwebbed. III longest, IV, II, and I sub- 
equal. Digital pads flattened, longer than wide, pointed (particularly III and IV), with 
circumferential grooves. Two flattened palmar tubercles; two indistinct conical tubercles 
between palmar tubercle and basal subarticular tubercle on finger IV; no ulnar or 
supernumerary tubercles. Toes long, unwebbed; IV, III, II, V, I in order of decreasing 
length; a pale, flattened inner metatarsal tubercle and a conical outer one; digital pads 
similar to those on fingers but slightly larger and more pointed. Heels touch when 
femora at right angles to body axis; TIB/SVL 49%. Vent directed posteriorly with an 
indistinct dark line above it. Skin of dorsum smooth with a few low, pale tubercles on 
hind limbs. Venter smooth, becoming faintly granular on thighs and near vent. 

Coloration of holotype. —In life, the dark chocolate brown dorsal stripes, more 
intense toward the snout where they meet, broke up at midbody and disappeared near 
the inguinal area. The middorsal area was lighter wood brown with an indistinct pale 
middorsal hairline beginning just above the vent and ending in the scapular area. The 
light dorsolateral stripes were tan, becoming silvery on upper eyelid and continuing to 
where they meet on the tip of the snout. The loreal area was medium brown with a 
darker spot at the anterior comer of each eye. A black lateral line started at the eye 
and continued over the tympanum to midbody, where it broke up into a series of spots, 
and ended. The legs were medium brown above, the thighs faintly and irregularly 
barred with darker brown. The posterior thighs were light brown with no bright colors 
on concealed surfaces or in groin. There was one dark brown blotch on the dorsolateral 
right forearm, two on the left, and a similar one on the anterior face of each humerus. 
The entire venter was uniform pale metallic yellow with a vague dusky suffusion on 
the throat. The iris was gold above and red-brown below. 

Morphological variation.— Nin&tQen adult females (including the holotype) have 
the following measurements (in mm) and proportions: SVL 15.5-18.4 (x = 17.0 ± 
0.80), HL 6.1-7.3 (6.9 ± 0.30), HW 6.4-7.6 (7.0 ± 0.32), TYM 1.0-1.3 (1.1 ± 0.1 1), 
EYE 2.1-2.8 (2.5 ± 0.16), NE 1.7-2.3 (2.0 ± 0.13), FEM 7.7-8.9 (8.3 ± 0.35), TIB 
7.4-8.5 (8.1 ± 0.29), FT 7.0-8.5 (7.9 ± 0.45), HW/SVL 39-42% (41 ± 0.74), TIB/ 
SVL 45-51% (47 ± 1.45). 

Thirty two adult males have the following measurements and proportions: SVL 
9.4-14.2 (12.5 ± 2.48), HL 3.9-6.0 (5.4 ± 0.42), HW 3.6-5.9 (5.3 ± 0.45), TYM 0.8- 
1.3 (1.1 ± 0.25), EYE 1.6-2.2 (2.0 ± 0.14), NE 1.0-1.8 (1.5 ± 0.18), FEM 4.6-7.7 
(6.2 ± 1.25), TIB 4.7-7.0 (6.3 ± 0.41), FT 4.0-6.6 (5.8 ± 1.16), HW/SVL 38-44% 
(40 ± 7.4), TIB/SVL 44-53% (49 ± 1.89). 

Morphological variation in the sample is comparatively slight, with a few excep- 
tions. Eyelid tubercles may be almost indistinguishable (as in the holotype) or prominent 
(USNM 250043). Digital discs may be distinctly pointed or rounded, and the heels 
may barely meet or may overlap considerably (see TIB/SVL ratios above). The head 
varies from slightly longer than broad to broader than long in both sexes. 

In contrast, both dorsal and ventral patterns are extremely variable. The dark spots 
on the forelimbs, body, and above the anus, and the hindlimb barring may be distinct, 
absent, or any condition in between. In the tricolor morph (see below), the dark dorsal 
stripes may be present only in the postocular area, extend to the inguinal area (Fig. 
2A), or break up near midbody as in the holotype. The middorsal hairline, when present, 
is usually confined to the posterior body but it can (rarely) extend onto the posterior 
thighs; one individual (USNM 250039) even had hairlines on the posterior tarsi. The 
pale spots and/or tubercles on the hindlimbs (see Fig. 1) are not visible in life but 
appear after preservation in some individuals. 

The ventral color is invariably yellow, often almost metallic. The dark pigmentation 
on the throat is quite variable, and may consist of obscure marbling or stippling, discrete 
dark blotches restricted to the edges of the mandible, or a general gray suffusion ex- 
tending to the pectoral area. Some individuals have distinct gray spots on the throat, 
similar to the characteristic pattern of E. grabhami. The extreme condition is found 
in the single juvenile (USNM 250007) in which the entire belly is marbled with gray. 



148 




Figure 1. Dorsal view of the holotype of Eleutherodactylus griphus (USNM 250000). SVL 16.4 mm. 



Pattern polymorphism. —Pattern variation in frogs of the genus Eleutherodactylus 
can be extreme and this has led to considerable taxonomic confusion (Lynch 1966). 
Jamaican frogs of the gossei group may have as many as 9 morphs in a single species 
(Goin 1954:193, fig. 2 and data presented below). Goin (1950, 1954) attempted to 
quantify this variation and standardize terminology for the various morphs. I previously 
discussed polymorphism in some members of the groups and suggested some changes 
in Goin's arrangement and terminology (Crombie 1977:198-199). 

Compared to other members of the gossei group, polymorphism in E. griphus is 
conservative {see Fig. 2), but some individuals may have a combination of two or three 
pattern elements regarded as distinct morphs by Goin {see below). 

The holotype and 14 other specimens of Eleutherodactylus griphus have light 
dorsolateral stripes (Figs. 1 , 2A) that start on the tip of the snout, continue across the 
eyelids and onto the lateral body, becoming much wider posteriorly {see coloration of 
the holotype for more complete description of this morph). This is not the dorsolateral 
stripe morph of Goin (1950, 1954), which consists of stripes that are more dorsal than 
lateral and approximately the same width anteriorly and posteriorly {see Lynn 1 940, 
PI. VI, fig. 1 Ic). Although Goin (1954) did not recognize these differently striped frogs 
as a distinct morph, Lynn (1940) illustrated a similar pattern for both E. gossei, which 
he incorrectly called luteolus (PI. IV, fig. 7d), and E. orcutti (PI. XII, fig. 23b). This is 
one of the most distinctive, albeit uncommon morphs in the gossei group and, for 
convenience, I propose to call it the "tricolor" morph, in allusion to the pale dorsolateral 
stripes, the dark outlining, and the less intensely dark middorsal area. 

The second morph o^ Eleutherodactylus griphus apparently does not occur in other 
members of the gossei group and I have called it "plain" (Fig. 2B). It consists of a 
basically unicolor dorsum, with or without a dark interocular bar. Roughly 50% of the 
present sample is this morph. 

The third morph was termed "purple" by Goin (1954:191) and was illustrated by 
Lynn (1940, PI. IV, fig. 7f). A few specimens of £". griphus compare well with the 



149 









B 



Figure 2. Dorsal and ventral view of the three commonest morphs of Eleutherodactylus griphus: A) tricolor, 
USNM 244471; B) plain, USNM 250041; C) purple, USNM 250038. 



description of this morph (Fig. 2C), previously found only in E. gossei (Goin 1 954: 191), 
but my collections document its presence in E. pentasyringos also (USNM 250949 and 
250971). 

Five (mottled, broad dorsolateral stripe, broad middorsal stripe, interocular bar, 
picket) of the seven other morphs in the gossei group are unknown in E. griphus. 
Although a dark interocular bar is common in the plain morph and may be faintly 
indicated in some tricolor frogs, it is different from Coin's interocular bar morph, which 
consists of a light bar, outlined with black. Pelvic spots, which I prefer to call lumbar 
spots (Crombie 1977:199), occasionally occur in the plain morph off", griphus. The 
middorsal stripe (=middorsal hairline) may also be indistinctly visible in both tricolor 
and plain morphs but it is restricted to the posterior body, never extending to the snout 
and rarely onto the thighs as it does in other members of the gossei group. 

Comparisons. —Eleutherodactylus griphus is only slightly larger than the smallest 
known Jamaican frog, E. sisyphodemus (males to 13.8, females to 17.9 mm SVL), with 
which it is syntopic in the Cockpit forests. However, as with many members of the 
genus, absolute morphological differences between E. griphus and sympatric congeners 
may not exist. Accurate identification may often depend on coloration in life, adver- 
tisement call, distribution, habitat, and other non-morphological characters that are 
difficult or impossible to assess in older museum specimens. Perhaps the best example 
in Jamaica is E. junori, a small (19-27 mm SVL) species with a distinctive, loud, 
rachet-like call, but otherwise indistinguishable from the slightly larger E. gossei. In 
the following discussion I have attempted to use distinguishing characters that do not 
depend on familiarity with the species in life whenever possible, but in some cases size 
and/or distribution must be used. 

I have previously (Crombie 1977:200) discussed the species groups of Jamaican 
Eleutherodactylus. Although there are conflicting data on this arrangement {see Rela- 



150 

tionships), it remains a convenient tool for making pertinent comparisons. Since E. 
griphus is clearly a member of the gossei group as previously defined (Crombie 1977), 
distinguishing it from the members of the very different auriculatus, jamaicensis or 
ricordii groups, with the exception of E. grabhami {see below) is unnecessary. 

The eastern endemics of the gossei group from the granitic Blue Mountains (£". 
alticola, E. andrewsi, E. nubicola, E. orcutti, and E. pentasyringos) are distributionally 
far removed from the range of -£". griphus. Most are much larger frogs that occur above 
2500 feet (810 m) in the mountains. The smallest of them, E. andrewsi (18-23 mm 
SVL), usually has a pale dorsum with distinct dark inguinal spots, a venter heavily 
pigmented with dark spots or a reticulum, and red flash colors in the inguinal areas 
and concealed thighs. Eleutherodactylus orcutti is a stream- or seep-inhabiting species 
with conspicuous basal toe webbing and a tuberculate dorsum; E. nubicola has poorly 
developed digital discs and a uniform gray belly, even in preservative; E. alticola is 
restricted to the highest peaks of the Blue Mountains, has very short vomerine series 
and red groin patches. I regard E. pentasyringos as a distinct species rather than a 
subspecies of £". pantoni. Schwartz and Fowler (1973: 1 18) suggested that the two might 
not be conspecific and my unpublished data confirm the morphological and acoustic 
differences between the two taxa. Although E. pentasyringos occurs in the lowlands 
north of the Blue Mountains and often has a pale yellow belly like E. griphus, it is a 
larger, more robust species with a loud six-note call. 

The most pertinent comparisons are with the six species of the gossei group with 
which E. griphus is actually or potentially sympatric and E. grabhami, a small sympatric 
member of the ricordii group. I previously (Crombie 1977:200) compared E. sisypho- 
demus with E. griphus (which I then called luteolus), concluding that the calcar, tarsal 
fringe, ulnar stripe, and black ventral coloration oi E. sisyphodemus distinguished even 
recently hatched specimens. 

Eleutherodactylus luteolus is generally found in more open areas then E. griphus 
but the two may be syntopic at the forest edge. Males are similarly sized but E. griphus 
is slightly smaller, with dark throat markings, and a bright yellow belly in life. All the 
E. luteolus I have collected have been singularly drab frogs, and I have not seen the reddish 
dorsal markings or pale yellow bellies mentioned by Schwartz and Fowler (1973:123- 
124). However, the prominent supra-axillary and inguinal glands of £". luteolus are 
visible even in preserved material and serve to distinguish it from all similar species. 

As previously mentioned, the throat markings of E. griphus may resemble those 
of E. grabhami, but the similarities end there. Eleutherodactylus grabhami is a pale, 
mottled frog (occasionally with broad dorsolateral light stripes) with fragile dorsal skin, 
a white belly, and pinkish hindlimbs and brachia. Although E. grabhami has been 
found less than a meter from individuals of £". griphus in the Cockpit forest, E. grabhami 
are usually up on limestone rocks as opposed to concealed in the leaf litter. Eleutherodac- 
tylus grabhami has also been found in terrestrial bromeliads and on low shrubs (Schwartz 
and Fowler 1973:8 1; Crombie, personal observation), indicating that it is more arboreal 
than E. griphus. 

The remaining four species, E. fuscus, E. gossei, E. junori, and E. pantoni, are very 
similar and often difficult to distinguish in the field, although their advertisement calls 
are very different. Perhaps the most distinctive is E. fuscus, which often has a bright 
yellow venter, orange or reddish in the groin and on the concealed legs, a continuous 
dark supra- and post-tympanic crescent, and a tubercular scapular "W." My obser- 
vations on the coloration of this species agree with those of Schwartz and Fowler (1973: 
119-120) rather than the original description, in which Lynn and Dent (1942:236) 
described the venter in life as "immaculate white." In ventral color, E. fuscus and E. 
griphus are similar, but E. griphus is a much smaller species {fuscus males 25-35, 
females 31-37 mm SVL), with distinct dark throat markings, canthal stripes and/or a 
facial mask, no bright colors in the groin or on concealed limbs, and smooth dorsal 
skin. Although many E. griphus may have both supra- and post-tympanic dark spots, 
they do not form a continuous crescent as in E. fuscus. Reportedly, one of the paratypes 



151 

ofE. fuscus (USNM 11 5978) was collected at Quick Step (Lynn and Dent 1942:235). 
However, I have never heard the distinctive call of this species in the southern Cockpits, 
so sympatry with E. griphus remains to be demonstrated. 

Like E. fuscus and E. griphus, E. pantoni has bright ventral coloration, ranging 
from yellow to burnt orange. Schwartz and Fowler (1973) recognized three subspecies 
of this widespread and variable frog, one of which (pentasyringos) I regard as a distinct 
species {see above). The southern Cockpit Country populations are intergradient be- 
tween E. p. pantoni and E. p. amiantus. Adults (to 40 mm +) have a prominent raised 
scapular "W" and cannot be confused with E. griphus; even juvenile E. pantoni lack 
dark canthal and lateral body stripes. 

As noted above, E. gossei and E. junori are virtually indistinguishable without 
information on the call so they will be considered together here. Eleutherodactylus 
junori is the smaller species (19-27 mm SVL vs. 28-34 mm in gossei), but both have 
prominent orange or pink patches in the groin and a raised (often outlined in brown) 
scapular "W," lacking in E. griphus. Some individuals of E. gossei may have a pale 
yellow belly (Schwartz and Fowler 1973:92; Crombie, personal observation) but it is 
usually dull white or ivory. Cockpit Country E. gossei also lack the dark canthal stripe 
or facial mask of £". griphus but this pattern may be present in E. gossei from localities 
to the east. 

Relationships. —Since studies on the relationships of Jamaican Eleutherodactylus 
based on osteology (Glenn Flores) and electrophoresis (Blair Hedges) are in progress, 
my speculative comments on the relationships of E. griphus will be brief. 

Although the preliminary osteological and electrophoretic data are not in agreement 
on the species groups of Jamaican Eleutherodactylus as I defined them (Crombie 1977), 
E. griphus is clearly more closely related to the members of the gossei group than to 
any other West Indian Eleutherodactylus. Pending the outcome of other studies, I 
continue to recognize the gossei group as a natural assemblage. 

There are two main centers of inter- and intra-specific diversity in the group, both 
associated with extremely mesic areas that were probably isolated during the drier 
periods of the Pleistocene (Pregill and Olson 1981). The higher elevations of the eastern 
Blue Mountains and their windward slopes harbour six endemic taxa of the gossei 
group and the western limestone region contains five, including E. griphus. It seems 
likely that E. griphus evolved from the widespread, ecologically versatile gossei-pantoni 
stock in the mesic enclave of the Cockpits. 

Natural history.— Eleutherodactylus griphus is the commonest leaf litter frog in 
the Cockpit forest and it has been collected on each of my visits to the area, as compared 
to E. sisyphodemus which was found on only two of five occasions. Both species are 
completely terrestrial and nocturnal but individuals can often be found by day, par- 
ticularly following afternoon rains. Eleutherodactylus griphus appears tolerant of drier 
conditions and, unlike E. sisyphodemus, it has been found in open areas (around tree 
falls) within the forest and on occasions when the leaf litter was less than saturated. 

Although E. griphus is largely confined to pockets of leaf litter in undisturbed 
forest, I collected a small series (USNM 250001-04) at the forest edge along the road 
north of Quick Step in 1977. They were found after dark in leaf litter along rock walls 
and cliffs, associated with E. cundalli, E. gossei, E. grabhami, E. luteolus and E. 
pantoni. Although I suspect that E. griphus is a Cockpit endemic, this apparent tolerance 
of disturbed areas may indicate a wider distribution. 

Although nests were not found in the field, 13 (42%) of the female paratypes were 
gravid and six others had distended, convoluted oviducts, suggesting recent reproduc- 
tive activity. The smallest of these adult females were 15.5 (convoluted oviducts, small 
ova) to 15.7 (gravid) mm SVL. Four of the 12 immature females were larger (15.6- 
16. 1 mm SVL) than the smallest adult female. Immature individuals were characterized 
by thin, straight oviducts and flattened, translucent ovaries with barely recognizable 
follicles. 

The one juvenile (USNM 250007, 6.5 mm SVL) appeared to be a recent hatchling 



152 

but a 9.4 mm individual (USNM 250034) had moderately enlarged, rounded, granular 
testes and was regarded as an adult. All the other males (11.0-14.2 mm SVL) had 
moderately to greatly enlarged testes and appeared to be reproductively active. 

The "soft call of £". luteolus'" {=griphus) I mentioned in my 1977 paper is actually 
that of £". sisyphodemus (Crombie MS). Despite considerable attention given to tracking 
calls in the leaf litter under favorable conditions on the 1983 trip, no call was heard 
that was attributable to E. griphus. 

Gut contents, examined superficially in skeletonized, cleared and stained, and 
selected preserved specimens, consisted primarily of ants, spiders, and small cock- 
roaches. However, two greatly distended individuals (USNM 250001, 14.2 mm SVL, 
and USNM 250042, 13.6 mm; both immature females) each contained a lepidopteran 
larva longer than their own body (18 and 15 mm, respectively). USNM 250001 also 
contained a few ants and cockroach legs. 

The type locality was discussed in some detail previously (Crombie 1977), but the 
area has changed somewhat since my first visit in 1971. In my 1977 paper I placed 
"the cave" at about 4 mi (6.4 km) WNW of Quick Step. This was based on a road 
distance of 2 miles (3.2 km) north of the village of Quick Step, then an estimated two 
mile overland walk roughly WNW of the road to the cave. Since that time the Quick 
Step road, formerly a treacherous mud and rock track that was impassible in wet 
weather, has been altered and improved. It is now paved as far as Quick Step and the 
unpaved stretch north to the cave trail is considerably smoother and less steep. In 
1983, the odometer reading from Quick Step P.O. to the beginning of the cave trail 
was 4.9 miles (7.8 km), resulting in the type locality (ca. 7 mi WNW Quick Step) as 
stated in the above description. Despite the slight mileage differences in my previous 
paper and this, the type localities off", griphus and E. sisyphodemus are the same cave. 
Recent work in the area by cavers has resulted in an excellent map of the cave (called 
Marta Tick Cave) and a general discussion of the area (Baker et al. 1986). 

A botanical survey of the Cockpits by Frank W. Davis (U.C. Santa Barbara) 
provides an expanded vegetational profile of the type locality. The cave is located on 
a 20-35° scree slope that is covered with slightly disturbed wet limestone forest (Asprey 
and Robbins 1953). The forest canopy is at 8-10 m but it is broken by emergents with 
heights to 33 m. Common tree species include Nectandra antillana, N. patens, Guarea 
schwartzii, Ficus sp., Calophyllum calaba, and Trichilia moschata. The fairly open 
shrub layer includes saplings of overstory species as well as Eugenia sp., Psychotria 
sp., Calyptwnomum occidentalis, and Quiina jamaicensis. A sparse herb layer is dom- 
inated by the trailing liana Syngonium auritum; other common lianas include Vitis 
tilliifolia and Cissus sycioides. Tillandsia antillana is a common large epiphyte. 

Etymology.— A noun in apposition, taken from the Greek "griphos," used idio- 
matically to refer to anything chaotic, confusing, or inexplicable. Given the 400 + 
species in the genus Eleutherodactylus and the bewildering variation and pattern poly- 
morphism exhibited by many species, I feel the combination is singularly appropriate. 
Although this species is not particularly variable compared to other Jamaican Eleu- 
therodactylus, the name also commemorates my initial confusion in mistaking E. 
griphus for E. luteolus, a thoroughly different species. 

Acknowledgments 

Since the discovery of Eleutherodactylus griphus is but one segment of a project 
begun in 1 970, 1 naturally owe a debt of gratitude to a great many people and institutions. 
I will try to thank these friends and colleagues adequately in future synthetic works but 
for now I mention only those who actively assisted in the Cockpit work. 

During the 1983 trip I benefitted greatly from the expertise and companionship 
of Frank W. Davis, Linda Gordon, Bill Hilgartner, Dyer Moore, Greg Pregill, Dave 
Steadman, and Richard Thomas. Frank Davis kindly provided the botanical profile of 
the type locality. In previous years Dick Franz, Barbara A. Harvey, Frances J. Irish 
(McCuUough), Jeremy F. Jacobs, and Fred G. Thompson all braved the rigors of the 
Cockpits with me. 



153 



As always, I am continually grateful to Menocal Stephenson of Quick Step, who 
has unselfishly shared his incomparable knowledge of the Cockpits and his home with 
me during my field work. His sons Jeffrey, Collin, John, and Win were of immeasureable 
help on our forays through the bush while Mrs. Stephenson and her daughters spared 
no effort to make us welcome and comfortable on our return to Quick Step. Another 
resident of Quick Step, particularly knowledgeable about the bush and inexplicably but 
affectionately known only as "Ratty," contributed much to the success of the 1983 trip 
and patiently tolerated many of our idiosyncracies. 

Over the years it has been a pleasure to work with Patrick Fairbaim of the De- 
partment of Natural Resources in Kingston, who efficiently processed our often eccentric 
permit requests and provided pleasant interludes on our visits to the big city. 

Funding for early exploratory work in the Cockpits was provided by a grant from 
the Penrose Fund of the American Philosophical Society (to RIC); the 1983 trip was 
supported by a National Geographic Society grant (#2482-82) to G. K. Pregill. Ad- 
ditional funds were received from the U.S. Fish & Wildlife Service through the late 
Howard W. Campbell, and the Alexander Wetmore Fund of the National Museum of 
Natural History. Thanks are due Bea Wetmore and Storrs L. Olson for facilitating the 
latter. 

Clarification of the status of £". griphus and E. luteolus would not have been possible 
without access to the Coleman J. Goin collections in the Carnegie Museum of Natural 
History; Ellen J. Censky and C. J. McCoy provided working space and innumerable 
courtesies during my visits to Pittsburgh. 

Molly Dwyer Griffin accurately and artistically rendered the drawings of the ho- 
lotype. Vic Krantz photographed the specimens, and Addison Wynn prepared Fig. 2. 

W. Ronald Heyer, Roy W. McDiarmid, Gregory K. Pregill, Robert P. Reynolds, 
David W. Steadman, and George R. Zug read and commented on the manuscript. Any 
unwarranted literary license occurs despite their protests and is my own responsibility. 
I have enjoyed discussions on Eleuthewdactylus with and have freely parasitized ideas 
from Glenn Flores, S. Blair Hedges, Ron Heyer, John D. Lynch, Roy McDiarmid, and 
Albert Schwartz. 



Literature Cited 



Asprey, G. F., and R. G. Robbins. 1953. The 
vegetation of Jamaica. Ecological Monographs 
23(4):359-412. 

Baker, Linda L., Edward A. Devine, and Michael 
A. Di Tonto. 1986. Jamaica. The 1985 ex- 
pedition of the NSS Jamaica Cockpits Project. 
National Speleological Society News 44(1):4- 
15. 

Barbour, Thomas. 1935. A second list of Antil- 
lean reptiles and amphibians. Zoologica 19(3): 
77-141. 

Crombie, Ronald I. 1977. A new species of the 
genus Eleuthewdactylus (Amphibia: Lepto- 
dactylidae) from the Cockpit Country of Ja- 
maica. Proceedings of the Biological Society of 
Washington 90(2): 194-204. 

Goin, Coleman J. 1950. Color pattern inheritance 
in some frogs of the genus Eleuthewdactylus. 
Bulletin of the Chicago Academy of Sciences 
9(1):1-15. 

. 1953. Rediscovery of the frog Lz/or/a /m- 

teola Gosse in Jamaica. Occasional Papers of 
the Museum of the Institute of Jamaica No. 7. 
1954. Remarks on the evolution of color 



pattern in the gossei group of the frog genus 
Eleuthewdactylus. Annals of the Carnegie Mu- 
seum 33(10):185-195. 
Lynch, John D. 1966. Multiple morphotypy and 



parallel polymorphism in some neotropical 
frogs. Systematic Zoology 15(1): 18-23. 

Lynn, W. Gardner. 1940. L Amphibians. Pp. 1- 
60 in W. G. Lynn and C. Grant. The Herpe- 
tology of Jamaica. Bulletin of the Institute of 
Jamaica, Science Series No. 1. 

, and James N. Dent. 1942. Notes on Ja- 
maican amphibians. Copeia (4):234-242. 

Myers, George S. 1938. Fresh-water fishes and 
West Indian zoogeography. Annual Report of 
the Smithsonian Institution for 1937, pp. 339- 
364. 

Pregill, Gregory K., and Storrs L. Olson. 1981. 
Zoogeography of West Indian vertebrates in 
relation to Pleistocene climatic cycles. Annual 
Review of Ecology and Systematics 12:75-98. 

Schwartz, Albert, and D. C. Fowler. 1973. The 
anura of Jamaica: a progress report. Studies on 
the Fauna of Curacao and other Caribbean Is- 
lands 43(142):50-142. 

, and Richard Thomas. 1975. A check-list 

of West Indian amphibians and reptiles. Car- 
negie Museum of Natural History Special Pub- 
lication No. 1. 

, , and Lewis D. Ober. 1978. First 

supplement to a check-list of West Indian am- 
phibians and reptiles. Carnegie Museum of 
Natural History Special Publication No. 5. 



"^ >^ TRANSACTIONS 

OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 




Volume 21 Number 10 pp. 155-165 5 December 1986 

A new night lizard {Xantusia hensham) from a sandstone 
habitat in San Diego County, California 

L. Lee Grismer 

Department of Biology, San Diego State University, San Diego, CA 92182 USA 

DEC i;:: 

Mark A. Galvan 

The Micromanipulator Microscope Company, 1461 N. Elm Street, 
Escondido, CA 92026 USA 

Abstract. A new subspecies of night lizard, Xantusia henshawi, is described and differentiated 
from X. h. henshawi and X. h. bolsonae based on the presence of an enlarged temporal scale, absence 
of enlarged auriculars, a narrower head and body, significantly fewer scales around the upper portions 
of the hindlimbs, no black peppering on the ventral surfaces of the limbs, a reduced dorsal pattern 
consisting of small round spots, no marked light and dark diel color phase, weakly defined vertebral 
furrow, and less scansorial habits. 

Introduction 

The geographical distribution of the Night Lizard genus Xantusia is notable for 
its numerous isolated populations (Webb 1965, 1970, Smith and Brodie 1982). Col- 
lectively, these populations comprise three species (Bezy 1972) ranging from northern 
Mexico and southwestern United States to the Channel Islands of California. In spite 
of this fragmented distribution, many populations are morphologically quite uniform 
within a species, yet the distinctiveness between others has promoted the recognition 
of several subspecies (Savage 1952, Webb 1965, 1970, Bezy 1967<3, b). We report here 
on another isolated population, one confined to a sandstone habitat in San Diego 
County, California, and sufficiently distinct morphologically, biochemically, behav- 
iorally, and in color pattern to warrent subspecific recognition within X. henshawi. 
Scale terminology follows Savage (1963) except where noted. All measurements and 
counts are taken from preserved specimens. 

Xantusia henshawi gracilis new subspecies 
Figure la 

Suggested common «am^.— Sandstone night lizard. 

Holotype.—SU^^H 64830, adult male collected by L. L. Grismer and M. A. 
Galvan on 17 February 1985 from the Truckhaven Rocks in the Anza-Borrego Desert 
State Park, located 24.5 km east and 6.3 km north of Borrego Springs, San Diego 
County, California. 

Paratypes.—Co\\QC\.Qd by authors at same locale as holotype. LACM 132488, 4 
April 1978; SDSNH 64824, 31 December 1979; SDSNH 64814-23, 1 December 1984; 
SDSNH 64804-1 1, 8 December 1984; SDSNH 64812-13, 9 December 1984; SDSNH 
64825-29, 17 February 1985. 

Diagnosis.— Xantusia henshawi gracilis differs from X. h. henshawi and X. h. 
bolsonae by having a greatly enlarged temporal scale equal to nearly one-half the size 
of the postparietal; absence of enlarged auriculars; absence of a vertebral furrow (in 



156 











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Figure 1 . a) Holotype of Xantusia henshawi gracilis, b) Left row X. h. gracilis, middle row X. h. henshawi, 
right row X. h. bolsonae. 



life); significantly different morphometric ratios concerning head depth/head width and 
interforelimb distance (Table 1 ); the lack of marked light and dark diel color phases; 
the almost complete absence of black peppering on all ventral surfaces; a reduced dorsal 
body pattern consisting primarily of small uniform round spots; and at least four fixed 
allelic differences out of 22 presumptive gene loci (Bezy and Sites 1986). Xantusia h. 
gracilis is significantly differentiated further from X. h. henshawi by having fewer scales 
around the upper arm and leg, higher number of supralabials, fewer longitudinal rows 
of dorsal scales, and a smaller interhindlimb distance/SVL (Table 1). Xantusia h. gracilis 
is significantly differentiated further from X. h. bolsonae by having a higher number 
of gular scales, fewer enlarged scales on pregular fold, a higher number of temporal 
scales, dorsal scales, and femoral pores (Table 1). 

Description of holotype.— Adult male SVL 59.6 mm; see Table 2 for other mea- 
surements; head triangular, slightly wider than neck; nostrils visible in dorsal view; eye 
large, closer to nostril than ear opening; ear opening elliptical, twice as high as wide, 
long axis directed anteroventrally; anterior pregular fold ventral to ear opening indicated 
by transverse row of reduced scales medially; posterior pregular fold six scale rows 
anterior to gular fold; gular fold indicated by large rectangular scales on edge, increasing 
in size medially and abruptly differentiated from scales on fold posteriorly; digits of 
pes and manus overlapping when limbs adpressed. 

Rostral slightly broader than high, with pointed dorsoposterior margin, followed 
in order by two nasals, a hexagonal frontoparietal, two prefrontals, a median, two 
frontals, a hexagonal interparietal separating two parietals, and two large postparietals; 
interparietal with conspicuous eye spot in posterior one-third; postparietals separated 
posteriorly by two small triangular interpostparietals that touch nuchals; nasals, pre- 



157 



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Table 2. Selected measurements (mm) of holotype SDSNH 64830. 



Tail length 82.2 

Head length (tip of snout to anterior of ear opening) 12.7 

Maximal head width anterior to ear opening 9.5 

Maximal head depth anterior to ear opening 5.7 

Tip of snout to posterior margin of postparietal 13.3 

Diameter of eye 3.0 

Anterior of eye to tip of snout 5.4 

Tip of snout to gular fold 19.6 

Length of right leg (insertion to tip of 4th toe) 27. 1 

Length of 4th toe 7.0 

Length of right arm (insertion to tip of 4th finger) 19.7 

Length of 4th finger 4.8 

Axilla-groin length 27.9 

Interforelimb distance 8.0 

Interhindlimb distance 6.4 



frontals, frontals, and postparietals in contact at midline; enlarged scales of head pitted 
throughout; nostril elliptical, bordering rostral, first supralabial, nasal, and postnasal, 
followed in order by postnasal, anterior loreal, loreal, and two loreolabials (dorsal 
loreolabial smaller), and small preocular scales of ocular ring; scales of ocular ring small, 
two postoculars largest; uppermost postocular touching fifth supraocular; five supra- 
oculars, third and fourth on left side with slightly damaged lateral margins; temporals 
nine (R) nine (L) (Fig. 4). Supralabials seven (R) eight (L); infralabials six (R) six (L); 
pretympanic scales decreasing in size ventrally; auricular scales slightly enlarged dor- 
sally; mental longer than broad; three large pairs of postmentals, first pair contacting 
medially; anteriormost four rows of gular scales largest; 43 transverse rows of gular 
scales (includes all scale rows between gular fold and first pair of postmentals), 20 rows 
between anterior postmental and anterior pregular fold, 1 7 rows between anterior and 
posterior pregular folds, and 6 rows between gular fold and posterior pregular fold, 
curving to the anteromedially; 10 enlarged rectangular scales on gular fold, increasing 
in size medially; five rows of small scales in gular fold, anterior row smallest. 

Back, sides, and limbs covered with granular scales; some brachials and femorals 
slightly enlarged; 19 (R) 22 (L) scales around upper arm and 27 (R) 27 (L) scales around 
upper leg; 14 longitudinal rows of rectangular ventrals at midbody, two bordering 
midline slightly narrower, lateralmost with curved lateral margins and slightly narrower 
adjacent ventrals; 30 transverse rows of ventral scales; one pair of enlarged preanal 
scales bordered posteriorly by six small precloacal scales, laterally by two larger scales, 
and anteriorly by three larger scales; 54 longitudinal rows of dorsal scales at midbody; 
130 transverse rows of middorsal scales from postparietals to posterior margin of 
hindlimb insertion; vertebral furrow of dorsum slightly evident in sacral region; 25 (R) 
24 (L) lamellae on fourth toe; nine femoral pores on each hindlimb; caudal scales 
rectangular roughly twice as wide ventrally as dorsally. 

Coloration of holotype in life. —Dorsal ground color of head, body, hindlimbs, and 
distal portion of forelimbs yellow to white; interorbital region bluish; ground color of 
all dorsal surfaces much more extensive than dorsal markings; proximal region of 
forelimbs white to pinkish; sides of body white; all ventral surfaces white with minute 
amounts of black peppering present only on lateral gular and ventral scales, pes, manus, 
and forelimbs; dorsal body pattern consisting of dark brown, small round spots; head 
plates anterior to parietals covered moderately with black peppering producing poorly 
defined blotches, largest posteriorly; small dark brown markings on dorsal surfaces of 
limbs present except on proximal portion of forelimbs; dark markings on side of head, 
neck, and body paler, and smaller than those dorsally; labial scales moderately punctate 
with black peppering; dark brown markings on tail confined to groups of scales, pro- 
ducing squarish markings; some scales of tail with black peppering, others immaculate. 



159 

Variation. —The paratypes approximate the holotype in general morphology. Most 
variation occurs in the presence of intercalary scales between some of the large dorsal 
head plates and, in some cases, their fusion to the anterior supraocular scales. In SDSNH 
64804 the frontoparietal is divided. In SDSNH 6481 1 the left parietal is divided into 
two larger lateral scales and one smaller medial scale, and the right parietal is incom- 
pletely divided. The right parietal is also completely divided in SDSNH 64822 In 
SDSNH 64808-09, 64815, 64818-20, 64822, 64826, and 64829 the temporals bor- 
dering the lateral margin of the postparietal are two to three times larger than those of 
other specimens. SDSNH 64816 has one interpost parietal. In SDSNH 64810 there is 
one slightly enlarged auricular dorsally and two in SDSNH 6481 1. In SDSNH 64808 
the third postmental on the left side reaches the lip and separates the third and fourth 
infralabials. The single pair of enlarged preanal scales in SDSNH 64809 is bordered 
anteriorly by three smaller scales. SDSNH 64807, 6481 1, 64817, 64819, and 64827- 
28 have two pairs of enlarged preanal scales and, with the exception of SDSNH 64807, 
have a small intercalary scale at their center, contacting all of them. In SDSNH 64808 
and 64820 there are three pairs of enlarged preanal scales. 

Generally, the paratypes approximate the holotype in basic features of coloration 
and pattern. The major difference is in LACM 132488, which almost entirely lacks 
dorsal spots and has a uniform tan-white ground color overlaid with a yellow reticulum 
(in life). IN SDSNH 64829 the dorsal spots are reduced and intermediate between 
LACM 132488 and the remaining paratypes. The dorsal body markings of SDSNH 
64804, 64815, 64818, 64821, 64827-28 are more irregular and slightly larger. There 
appears to be a slight ontogenetic change in dorsal body blotching, with markings 
becoming more rounded and better defined in larger specimens (Fig. lb). The ventral 
peppering of most paratypes is slightly less concentrated than that of the holtoype, 
manifesting itself in SDSNH 64813, 64827, 64829, and LACM 132488 which have 
almost a complete absence of black peppering on the ventral surfaces. 

The smallest two individuals are SDSNH 64806 and 64814 at 30.5 mm SVL and 
30.7 mm SVL, respectively, and the largest two individuals are SDSNH 64804 and 
64812 at 70.5 mm SVL and 70.8 mm SVL, respectively. Adult males have larger, 
better developed femoral pores than females and show a slight swelling posterior to 
the vent. 

Etymology. —The adjectival name gracilis, meaning slender, comes from the Latin 
root gracil, and pertains to this population's slender habitus. 

Comparisons with other subspecies.— A total of 139 specimens of Xantusia hen- 
shawi henshawi from the eastern most portion of its range in Riverside, San Diego, 
and Imperial Counties was examined. These specimens showed major geographic vari- 
ation in numbers of femoral pores and temporal scales. Specimens from Riverside 
County had an average of 23.8 (18-30) femoral pores (count includes both legs) and 
an average temporal scale count of 7.9 (7-1 1). Those of San Diego and Imperial Counties 
had combined averages of 17.4 (12-22) femoral pores and 8.4 (6-1 1) temporals. Webb 
(1970) also noted a similar cline in these counts for X. h. henshawi. A total of 19 X. 
h. bolsonae was examined and showed no noteworthy intrapopulational variation. 

Xantusia henshawi gracilis is more terrestrial and less scansorial than other sub- 
species of X henshawi {see below) being less of an obligate exfoliation-dwelling lizard. 
Presumably, this is reflected in its narrower head (greater head depth/head width ratio 
[Table 1]), body (smaller interlimb distances [Fig. 2a] and significantly fewer dorsal 
scales at midbody [Table 1 ]), and thinner limbs (significantly fewer rows of scales around 
their proximal portions [Table 1]) (Fig. 3). The interlimb distances and average limb 
growth rates seem to be reliable diagnostic characters for X. h. gracilis, although de- 
termining the point of limb insertion on the body is somewhat arbitrary, which is 
probably reflected in the wide range of measurements (Table I). 

Neonate, juvenile, and subadult Xantusia henshawi gracilis have longer limbs than 
comparably-sized X. h. henshawi. The limbs of X. h. henshawi. however, grow signif- 
icantly faster, so that at snout-vent lengths of 60 mm to 70 mm their limb length/SVL 



160 




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Figure 3. Top. Adult Xantusia henshawi henshawi from Ranchita, San Diego County, California. Bottom. 
Adult X. h. gracilis from Truckhaven Rocks, San Diego County, California. 



ratios approach those of X. h. gracilis (Fig. 2b). The hindlimbs of X. h. bolsonae are 
relatively shorter than the hindlimbs of X. h. gracilis and X. h. henshawi, whereas their 
forelimbs are longer. 

Xantusia henshawi gracilis has a greatly enlarged temporal scale that is nearly one- 
half the size of the postparietal. That of X h. henshawi is also enlarged, but equals less 
than one-quarter the size of the postparietal (Fig. 4). The temporal scale in X. h. bolsonae 
is much smaller and only slightly enlarged in some specimens. This is a particularly 
useful character for diagnosing X. h. gracilis because it does not vary, whereas other 
head scales do so considerably {see variation of paratypes for X. h. gracilis). 

Field and laboratory observations indicate that Xantusia henshawi gracilis does 
not exhibit marked light and dark diel color phases that are common in X. h. henshawi 
(Atsatt 1939). Compared with X. h. henshawi, they appear to remain in the light phase, 
which is further accentuated by the reduction of dark dorsal markings to small, round 
spots, rather than large, irregular blotches (Fig. 1). In one specimen (LACM 132488), 
the dorsal markings are almost absent. Some X. h. henshawi from Imperial County 
approach the color pattern of X. h. gracilis when in their light phase, but differ in 
having much larger dorsal markings (see top two specimens of middle row in Fig. 1 b). 
The ventral coloring of X. h. gracilis is for the most part immaculate, there being only 
a slight amount of black peppering on the limb and lateral gular surfaces in some 
specimens. Xantusia h. henshawi, on the other hand has extensive peppering on the 
ventral surface of the head, body, limbs, and tail. The ventral markings of X h. bolsonae 
are less extensive than those of X. h. henshawi on the head and body but nearly equal 
on the limbs and tail. 

Biochemical comparisons.— A preliminary allozyme analysis suggests that Xan- 
tusia henshawi henshawi and X. h. gracilis are sister taxa, based on the presence of 
three unique alleles; two of these are unique among xantusiids and one is unique among 
Xantusia (Bezy and Sites 1986). The data also demonstrate that X. h. gracilis and X. 
h. henshawi are separated by a genetic distance of 0. 1 88 with four fixed allelic differences 
out of 22 presumptive gene loci. The level of allozyme divergence is comparable to 



162 



PARIETAL 

TEMPORAL 

POSTPARIETAL 





Figure 4. Heads of Xantusia henshawi henshawi and X. h. gracilis demonstrating difference in size of 
temporal scale, a) Xantusia h. henshawi SDSNH 57395, SVL = 65.7 mm. b) Holotype of X. h. gracilis 
SDSNH 64830, SVL = 59.6 mm. Scale equals 5 mm. 

that between several subspecies of X. vigilis. Xantusia h. bolsonae appears to be most 
closely related to the sympatric X. v. extorris (Webb 1965) and should probably be 
considered as a separate species (Bezy and Sites 1986). Xantusia h. gracilis also appears 
to differ from X. h. henshawi in the expression of certain lactate dehydrogenase enzymes 
(Sites etal. 1986). 

Traditionally, the rank of subspecies has accounted for geographic variation ob- 
served in peripherially located, interbreeding parapatric populations. Where allopatry 
is the case, such as in Xantusia henshawi henshawi and X. h. gracilis, intergradation 
is not possible and other criteria must be employed. Since the morphological and 
biochemical data suggest that these two populations are sister groups, and their level 
of divergence is similar to that between several subspecies of X vigilis (Savage 1952, 
Webb 1965, Bezy 1967a, b, Bezy and Sites 1986, Sites et al. 1986), we elect to place 
gracilis in X. henshawi. 

Behavioral observations. —Four specimens of Xantusia henshawi gracilis (SDSNH 
64823, 64826-28) were maintained alive for a period of two weeks at room temperature 
in a 9.7 liter glass terrarium. Pieces of sandstone were placed in the terrarium to provide 
retreats. Five specimens of Xantusia h. henshawi were maintained under identical 
conditions in a separate terrarium, except they were provided with granitic flakes. Both 
terraria were kept side by side and observed at least once a night for a minimum of 
thirty minutes between 18:00 and 23:00 hours. A 25 watt red light bulb was suspended 
approximately one meter above the terraria to provide illumination for observation. 

All specimens of Xantusia henshawi gracilis were always abroad at night during 
the observation periods, and on several occasions were observed digging at the bases 
of the rocks placed on the substrate. Subsequently, they would place their head into 
the hole, withdraw it, and repeat the process at a different spot beside the same or 
different rock. 

The Xantusia henshawi henshawi spent most of their time concealed (only two 
specimens observed on four of 14 observation periods) and, when abroad, remained 
on the granite flakes. Conversely, X. h. gracilis spent roughly as much time on the 
substrate moving about the enclosure as on the sandstone. 

In another 9.7 liter glass terrarium three Xantusia henshawi gracilis, four X. h. 
henshawi, and four Phyllodactylus xanti were kept together. On 13 May 1986, two 



163 







c 

« 


'■s  


1 


■J*>-:. 




■>|P'-' 


1| 




»4 





Figure 5. a) Southern view of Truckhaven Rocks, San Diego County, California, b) Slabs of exfoliating 
sandstone, c) Rodent burrows in sandstone. 



164 



clutches of two eggs each of P. xanti were observed on a horizontal piece of sandstone. 
One of the X. h. gracilis approached an egg, grasped the end of it in its mouth, and 
began pulling on it while trying to walk backwards. Consequently, the end of the egg 
broke off and the lizard ate the part of the shell that remained in its mouth. It then 
placed its head inside the egg and began lapping up the yolk. When the two other X. 
h. gracilis approached the eggs they were chased away by the lizard that was eating. 
One of these other lizards then went to an undisturbed egg and repeated the process 
of breaking it open as described above. Combat between all three X. h. gracilis followed 
with various individuals having dominance over the others until eventually the yolk 
of all four eggs had been devoured. Following this, they all shared equally in eating the 
remaining empty shell cases. Interestingly, none of the X. h. henshawi showed any 
interest in the eggs even though they had equal access to them. 

The fact that all three Xantusia henshawi gracilis were eating and fighting over the 
eggs, and that they all broke and devoured the eggs in the same manner, suggests that 
this behavior is not a chance event induced by captivity, but a part of their behavioral 
repertoire. Conceivably, this was why we were unable to find but one Phyllodactylns 
xanti in the Truckhaven Rocks although in the peripheral regions where X. henshawi 
is presumably absent, P. xanti seemed to be in unusual abundance {see below). 

Habitat and distribution. —Xantusia henshawi gracilis is found within the bound- 
aries of the Anza-Borrego Desert State Park in a small circumscribed region known as 
the Truckhaven Rocks, approximately 240 m to 305 m elevation. This area is part of 
the southeastern flank of the Santa Rosa Mountains in northeast San Diego County. 
It is roughly 3 km long east to west and 1.3 km wide north to south. The Truckhaven 
Rocks have a complex and as yet unresolved geomorphological history. The region is 
composed of sandstone and siltstone sediments (Hoover 1965) of unknown age, and 
it is not certain if its emergence was concomitant with the uplift of the Santa Rosa 
Mountains (Threet 1974), or the result of an eastward strike-slip displacement along 
the San Jacinto fault (Sharp 1972). In either case, the sandstone has subsequently 
undergone tremendous erosion (Fig. 5a) resulting in several arroyos 30 m to 60 m deep, 
running northwest to southeast. 

Xantusia henshawi gracilis is the only known xantusiid from a sandstone habitat. 
Compared to other Xantusia henshawi, its relatively slender physique presumably 
allows it to exploit the wide range of microhabitats produced by the eroding substrate, 
as opposed to being restricted to exfoliating microhabitats even though these are also 
present (Fig. 5b). Some specimens were unearthed in what appeared to be rodent 
burrows atop piles of hardened siltstone (Fig. 5c). Also, the reduced dorsal markings 
and lightened color pattern appears more cryptic on the tan-colored sandstone. 

Specimens were collected at both the western and eastern extremes of the habitat, 
but within this region Xantusia henshawi gracilis seems to be more abundant in lo- 
calized areas and not evenly distributed. 

The nearest reported locality for X. h. henshawi is approximately 38 km to the 
southwest from Oak Grove (Lee 1976, Julian Lee, personal communication 1985). We 
report two additional specimens from Borrego-Palm Canyon (SDSNH 39426 and 4 1 090), 
reducing this distance to 32 km. According to Lee (1976), X. h. henshawi is found on 
both the coastal and desert slopes of the Santa Rosa Mountains. The Santa Rosa 
Mountains, however, run northwest to southeast and have no coastal slope; his locality 
data show specimens to be present in only the extreme northwest portion. We searched 
all arroyos on the south facing side of the Santa Rosa Mountains between the Truck- 
haven Rocks and the nearest reported X. h. henshawi locality, as well as those accessible 
arroyos on the northeastern side. Although the habitat appeared suitable in some places 
for X. h. henshawi, none was found. There did, however, seem to be an unusual 
abundance of Phyllodactylus xanti. 

Material examined.— Xantusia henshawi bolsonae LACM 5595-64, 72324-25, 
76156-59, 106803-06, 116260-61. Xantusia henshawi gracilis SDSNH 64804-30, 
LACM 132488. Xantusia henshawi henshawi Riverside County: SDSNH 10872-76, 
23364, 23367, 31517-18, 31571-614, 34740-61, 38042, 62304. San Diego County: 



165 



SDSNH 13368-70, 18484, 18505-06, 18653, 18639, 19039, 26891, 35495, 36347 
39371-73, 39421-26, 3991 1-12, 40206, 41002-03, 41090. Imperial County: SDSNH 
20021, 23695, 26826-27, 49882, 57398-401, 57404, 57685-97, 57690-97 58392- 
94, 59266-68, 59432, 60128-34. 

Acknowledgments 

Many friends and colleagues helped in various phases of this study. For field 
assistance we wish to thank Jim and Barry Sherman, Larry Grismer, Frankie Grismer, 
Don Barrios, and Edith Wise. Richard E. Etheridge, Richard Estes, Robert L. Bezy] 
John R. Ottley, Hobart M. Smith, Douglas D. Edwards, and Julian C. Lee provided 
helpful comments on various drafts of the manuscript. We wish to thank Fred Jee for 
help in finding pertainent geological literature. For the loan of specimens we wish to 
thank Robert L. Bezy of the Los Angeles County Museum of Natural History (LACM) 
and Gregory K. Pregill of the San Diego Natural History Museum (SDSNH). We wish 
to express special thanks to our good friend Mark Jorgenson of the Anza-Borrego Desert 
State Park who personally facilitated the speedy procurement of the necessary permits 
required to collect within the park boundaries. To him we owe many favors. 



Literature Cited 



Atsatt, S. R. 1939. Color changes as controlled 
by temperature and light in the lizards of the 
desert regions of southern California. Univer- 
sity of California (Los Angeles) Publications in 
Biological Sciences 1:237-276. 

Bezy, R. L. 1967(3. A new night lizard (A'amjis/a 
vigilis sierrae) from the southwestern Sierra 
California. Journal of Arizona Academy of Sci- 
ences 4:163-167. 

. 1967^. Variation, distribution, and taxo- 

nomic status of the Arizona night lizard {Xan- 
tusia arizonae). Copeia 1967:653-661. 

. 1972. Karyotypic variation and evolution 

of the lizards in the family Xantusiidae. Los 
Angeles County Natural History Museum 
Contributions in Science 227:1-27. 
-, and J. W. Sites, Jr. 1986. A preliminary 



analysis of allozyme evolution in the lizard 
family Xantusiidae. Herpetologica, in press. 

Hoover, R. A. 1965. Areal geology and physical 
stratigraphy of a portion of the southern Santa 
Rosa Mountains, San Diego County, Califor- 
nia. Unpublished Masters Thesis, University 
of California, Riverside. Pp. 1-81. 

Lee, J. C. 1976. Xantusia henshawi.CaiaXogueoi 
American Amphibians and Reptiles. P. 189. 

Savage, J. M. 1952. Studies on the lizard family 
Xantusiidae. I. The systematic status of the 
Baja California night lizards allied to Xantusia 
vigilis, with the description of a new subspecies. 
American Midland Naturalist 48:467-497. 



. 1963. Studies on the lizard family Xan- 
tusiidae. IV. The genera. Los Angeles County 
Natural History Museum Contributions in Sci- 
ence 71:1-38. 

Sharp, R. V. 1972. Tectonic setting of the Salton 
trough. Pp. 3-1 3 m R. v. Sharp (ed.). The Bor- 
rego Mountain Earthquake of April 9, 1968. 
United States Geological Survey Professional 
Paper 787. 

Sites, Jr., J. W., R. L. Bezy, and P. Thompson. 
1986. Nonrandom expression of lactate de- 
hydrogenase isozymes in the lizard family 
Xantusiidae (Reptilia, Sauna). Biochemical 
Systematics and Ecology, in press. 

Smith, H.M., and E.D.Brodie, Jr. 1982. A Guide 
to Field Identification. Reptiles of North 
America. Golden Press, New York, New York. 

Threet, R. L. 1974. Alternative interpretations for 
the southern portion of the San Jacinto fault 
zone. Pp. 25-38 in M. W. Hart and R. J. Dow- 
len (eds.). Recent Geologic and Hydrologic 
Studies, Eastern San Diego County and Ad- 
jacent Areas. San Diego Association of Geol- 
ogists, San Diego, California. 

Webb, R. G. 1965. A new night lizard (genus 
Xantusia) from Durango, Mexico. American 
Museum Novitates 2231:1-16. 

. 1970. Another new night lizard (Xantu- 
sia) from Durango, Mexico. Los Angeles County 
Natural History Museum Contributions in Sci- 
ence 194:1-10. 




TRANSACTIONS 
OF THE SAN DIEGO 
SOCIETY OF 
NATURAL HISTORY 



Volume 21 Number 11 pp. 167-202 5 December 1986 



The evolution of helodermatid squamates, with description of a 
new taxon and an overview of Varanoidea 

Gregory K. Pregill 

San Diego Natural History Museum, P.O. Box 1390, San Diego, California 92112 USA 

Jacques A. Gauthier ")FC i' 

Museum of Zoology. University of Michigan, Ann Arbor, Michigan 48109 USA 

Harry W. Greene 

Museum of Vertebrate Zoology and Department of Zoology, University of California, Berkeley, California 
94720 USA 

Abstract. New fossils of helodermatid squamates from the early Miocene of Nebraska prompted 
us to examine all known material actually or potentially referrable to Helodermatidae. Although rep- 
resented today only by two species ranging from southwestern United States south to Guatemala, the 
fossil record of Helodermatidae encompasses the Late Eocene of France, and the latest Paleocene to 
Recent of North America. If Paraderma bogerti Estes is a helodermatid, as we contend, Helodermatidae 
extends to the late Cretaceous in North America. Extinct lanthanotines and varanines from the late 
Cretaceous of Mongolia, together forming the sister taxon (Varanidae) of Helodermatidae, confirm the 
antiquity of these groups. 

From early in their history the principal morphological specialization of helodermatids has been 
their powerful, stoutly constructed jaws capable of crushing large prey; living Heloderma may consume 
proportionally larger prey than any other squamate aside from certain snakes. Teeth grooved for venom 
delivery appear in all Cenozoic helodermatids, but that attribute is fully elaborated only in the two 
extant species, Heloderma horridum and H. suspectum. 

Within Helodermatidae, Eurheloderma gallicum Hoffstetter is distinguished by a markedly con- 
stricted parietal, an attribute that may be ancestral for Varanoidea. A similarly constricted helodermatid 
parietal is herein reported from the latest Paleocene of Wyoming. Because of the diagnostic triangular 
frontal bones, we reassign the late Oligocene-early Miocene species Heloderma mattheni Gilmore to 
a new taxon, Lowesaurus. We reexamine its contemporary, Heloderma texanum Stevens, from the 
early Miocene of Texas, and infer its relationship with living Heloderma according to osteoderm 
morphology and a wide basal opening of the venom groove. 

By necessity, our evaluation of helodermatid phylogeny requires a review of character states found 
in their sister taxon, Varanidae (Lanthanotinae + Varaninae). We clarify a number of morphological 
features such as the structure of the intramandibular joint and retraction of the bony nares. Monophyly 
of the group Helodermatidae + Varanidae is easily documented, and we restrict the name Varanoidea 
to that taxon. However, the phylogeny of a more encompassing taxon, Platynota, is ambiguous and 
we recommend that designation only as a term of convenience, to include varanoids and those other 
taxa with which they have been traditionally associated ("Necrosauridae," Mosasauridae, Aigialo- 
sauridae, and Dolichosauridae). 

Our interpretations of helodermatid phylogeny are consistent with morphological evidence, and 
with behavioral and ecological aspects of their feeding biology. 

Introduction 

Prior to Gilmore's (1928) review of the fossil lizards of North America, nearly all 
lizard remains with hexagonal cephalic osteoderms had been assigned to Helodermat- 
idae. Gilmore (1928) restricted the taxon to the two living species, Heloderma suspec- 
tum Cope (Gila monster) and H. horridum Wiegmann (Beaded lizard), and a new 
species, H. matthewi Gilmore, based on a partial maxilla from the Middle Oligocene 



168 

(Orellan) of Colorado that exhibited the group's unique dentition: grooved teeth used 
for venom delivery. Fossils previously assigned to helodermatids (e.g., by Nopsca 1908) 
were referred to Anguidae (viz., Glyptosaurinae; see Sullivan 1979). After Gilmore's 
(1928) revision, no additional fossils of helodermatids were described until 1957 when 
Eurheloderma gallicum Hoffstetter was reported from the late Eocene/early Oligocene 
Phosphorites du Quercy of France (Hoffstetter 1957). Subsequently, more material of 
E. gallicum was reported from the phosporite locality at Escamps (DeBonis et al. 1 973). 
Currently, the species is represented by maxillae, a dentary, pterygoids, parietals and 
vertebrae. 

In the last decade, additional fossils of North American helodermatids were found 
in deposits of the White River Formation of Colorado (late Oligocene-Whitneyan). 
This material consists of dentaries, maxillae, frontals, parietals and other cranial frag- 
ments, all of which Yatkola (1976) referred to Heloderma matthewi. In his discussion 
of the helodermatid fossil record, Yatkola concluded that all lizards possessing teeth 
grooved for venom conduction were sufficiently similar to be included in a single genus, 
Heloderma. He thus relegated Eurheloderma Hoffstetter to synonymy. 

Shortly after Yatkola's (1976) paper was published, Larry Martin (University of 
Kansas) provided us with a frontal bone and two vertebrae collected from early Miocene 
deposits of Nebraska. These fossils are helodermatid, as described below, and are 
comparable to other middle Tertiary specimens that have been assigned to Heloderma 
matthewi, but we believe that they comprise a taxon diagnoseable from Heloderma 
proper. In the early Miocene, Heloderma was represented by H. texanum Stevens, a 
species described from a remarkably complete skull found in the Castolon Local Fauna 
of Big Bend, Texas (Stevens 1977); however, its relationship with other helodermatids 
was not considered at the time of its description (Stevens 1977). 

Finally, Bartels (1983) has described a varanoid parietal collected from the latest 
Paleocene of the Bighorn Basin, Wyoming. That fossil, too, is from a helodermatid, as 
discussed below. 

McDowell and Bogert (1954) were the first to place helodermatids in a systematic 
framework that combined them with Varanus and Lanthanotus as a group distinct 
from other extant anguimorph squamates. McDowell and Bogert ( 1954) altered Romer's 
(1956) classification by removing Lanthanotus from Helodermatidae and placing it 
closer to Varanidae. They assigned Helodermatidae to Varanoidea instead of Anguioi- 
dea (Diploglossa), and recommended the designation "Varanoidea" over "Platynota." 
Hence, Varanoidea included Varanidae, Lanthanotidae, Helodermatidae, and the ex- 
tinct families Dolichosauridae, "Aigialosauridae" and Mosasauridae. With some mod- 
ifications, Rieppel (1 980a) corroborated their conclusions, but used the name Platynota 
for this taxon. In that paper and in a companion study on the postcranial osteology of 
Lanthanotus (Rieppel 1980Z?), he regarded the three extant families as a monophyletic 
assemblage within the more inclusive Platynota. Elsewhere, Gauthier (1982) discussed 
Varanoidea with reference to the articulation between the dentary and post-dentary 
bones, a character complex providing insight into anguimorph phylogeny. 

The evolutionary history becomes cluttered, however, in consideration of several 
fossils from the late Cretaceous of North America and Asia, and the Paleogene of 
Europe that can be interpreted as at or near the base of helodermatid and varanoid 
phylogeny. For example, Estes (1964) proposed Parasaniwidae to accommodate two 
taxa from the late Cretaceous Lance Formation of Wyoming: Parasaniwa wyomingensis 
Gilmore and Paraderma bogerti Estes. More recently Estes (1983a) synonymized Par- 
asaniwidae with the more inclusive designation Necrosauridae Hoffstetter, a family 
constituted by Estes to include Necrosaurus, Parasaniwa, Eosaniwa, Provaranasaurus, 
and Colpodontosaurus. 

Paraderma bogerti is in ways similar to necrosaurids but remains even more 
problematical, primarily because it is so poorly represented by fossils. We regard it as 
the earliest known member of Helodermatidae. 

Borsuk-Bialynicka (1984) described several new anguimorphs collected from Up- 
per Cretaceous deposits of Mongolia. Two of these, Proplatynotia longirostrata and 



169 

Gobidenna pulchrum, she referred to as "necrosaurian grade lizards," primitive platy- 
notans whose relationships among anguimorphs remain problematic. Furthermore, 
Gobidenna possesses a few features described as Hcloderma-\ike. Besides these taxa, 
Borsuk-Bialynicka (1984) reported the first known remains of a fossil lanthanotine, 
Cherminotus longifrons, a new varanine, Saniwides mongoliensis, as well as additional 
material of the enigmatic varanid Tel masaurus granger! Gilmore. These new varanoids, 
though difficult to place unambiguously, do suggest that the lineages represented by 
Heloderma, Lanthanotus and Varanus are of considerable antiquity. The incomplete 
nature of the Cretaceous fossils makes their early history difficult to resolve. 

The discovery of these new helodermatid and varanid fossils, and our interpretation 
of novel characters, inspired this review of helodermatid phylogeny. The paper is 
organized into three parts. Part I reviews the diagnosis of Varanoidea in an attempt to 
clarify those characters that have been troublesome and ambiguous. We then (Part II) 
describe the new helodermatid fossils from the early Miocene of Nebraska, and discuss 
another from the latest Paleocene of Wyoming. In light of these we reinterpret Helo- 
derma texanum and those fossils previously assigned to H. matthewi in a discussion 
of the diagnostic features of Helodermatidae. A phylogeny based on this evidence is 
presented. Having this background, together with information from Part III on their 
natural history, we propose that the principal specialization of helodermatid squamates 
is a distinctive feeding mode. This is readily observed in the stout jaws and sturdily 
constructed skull architecture designed for crushing large prey. Venom delivery occurs 
in the more derived species as a superimposed specialization. For these reasons we will 
argue for the inclusion of Paraderma bogerti in Helodermatidae. We conclude our 
presentation of helodermatid phylogeny based on morphology by demonstrating (Part 
III) some concomitant associations with the natural history, behavior, and feeding 
biology of captive and wild animals. 

Materials and Methods 
Museum abbreviations of catalogued specimens: 

AMNH American Museum of Natural History, New York 

BHB Bayard H. Brattstrom, California State University, Fullerton 
KU University of Kansas Museum of Natural History, Lawrence 
KUVP University of Kansas, Vertebrate Paleontology, Lawrence 
MVZ Museum of Vertebrate Zoology, University of California, Berkeley 

PU Princeton University 
REE Richard Etheridge, San Diego State University 
SDSNH San Diego Natural History Museum 

TM Texas Memorial Museum, University of Texas, Austin 
UCMP University of California Museum of Paleontology, Berkeley 
UMMZ Museum of Zoology, University of Michigan, Ann Arbor 
UMMP Museum of Paleontology, University of Michigan, Ann Arbor 
UNSM University of Nebraska State Museum, Lincoln 

WP William Presch, California State University, Fullerton 

Specimens Examined. 

Skeletons of Recent Heloderma. -H. horridum AMNH 7216, 56439, 57768, 
57863, 64128; MVZ 79417; SDSNH 8906, 55596, 59469; REE 802; UCMP 1 17512, 
1 18927, 1 18928, 123071, 131263, 131264, 131265; UMMZ 149609, 181151, 181637; 
WP 648. 

H. suspectum AMNH 56432, 66998, 71082, 71864, 72646, 72748, 72908, 72999, 
73771 74777, 74778, 109521; BHB 802, 3158; KU 129, 1 173, 13998, 23002-23010, 
78906- MVZ 6313, 29398, 64208, 95990, 128983; SDSNH 55287, 57084, 62991; 
REE 1030, 1026, 1029; UCMP 117511, 131261, 131262; UMMZ 128115, 130160, 
149610, 149611, 173549, 173550, 178528, 178529, 180467, 181130, 181638, 181640, 
181641; WP 120, 235, 649, 650, 651, 652, 687 (skull only). 



170 

Two frozen specimens of H. suspectum were available for dissection (SDSNH 

uncat.)- 

Skeletons of Recent varanids. — Lanthanotus borneensis REE 1445. Varanus ben- 
galensis SDSNH 57081, 60436, 60437; UMMZ 128572, 130172. V. exanthematicus 
REE 1987; UMMZ 151113. V. komodoensis UMMZ 149612. V. nebulosus SDSNH 
26058. V. niloticus SDSNH 55279, 63815; UMMZ 149613. V. prasinus SDSNH 
57082, 59468, 60438, 60441. V. sahator SDSNH 57080; UMMZ 128112, 128113, 
130167, 149614, 149615, 168411, 173096. V. var/w5 AMNH 28698. 

Fossils. -Paraderma bogerti UCMP 49939, 49895, 49940, 54199, 54213, 54261 
(holotype); Heloderma matthewi AMNH 990A (holotype), KUVP 7652, 4965 1, 49652, 
UNSM 5001 1; H. texanum TM 40635-1 19, -123 (holotype), 40635-137, -138, -140; 
Eurheloderma gallicum PU 12280; helodermatid parietal UMMP 74619. 

Osteological terminology follows Estes (1983a), McDowell and Bogert (1954) and 
Meszoely (1970). 

Our method of assessing character polarity follows the recommendations of Mad- 
dison et al. (1984). Monophyletic taxa successively removed from Helodermatidae 
were consulted as the need arose. Although not formally considered in this analysis, 
the Mongolian Cretaceous varanoids described by Borsuk-Bialynick (1984) also were 
evaluated to help resolve cases of character ambiguity. In several instances, so noted, 
multi-state characters were recoded in order to achieve consistency in coding all char- 
acters in standard binary fashion (0 = ancestral; 1 = derived; 9 = missing data). A 
character matrix was compiled and subjected to computer analysis using Swofford's 
(1984) PAUP program installed at the University of Michigan, and PHYSYS available 
through the California State University system (CSU CYBER). The results of these 
procedures were used mainly as a check of our own analyses. 

I. Varanoidea 

Because our polarity assessment of helodermatid characters relies on their distri- 
bution first among Varaninae and Lanthanotinae and second among other anguimorphs, 
it is necessary to review the attributes of Varanoidea that others have considered 
diagnostic. This review collates a scattered literature on the subject, but essentially the 
purpose is for assessing relationships within helodermatids in the context of character 
distribution within their sister taxa. 

The following characters (and character complexes) have been considered diag- 
nostic for Varanoidea, several of which require comment. Parenthetical numbers denote 
the corresponding character(s) in Tables 2 and 3. 

McDowell and Bogert (1954) (also Romer 1956): 

A. Loss of caudal autotomy (52). 

B. More deeply cleft fore-tongue (notched not less than 20% of length) (71). 

C. Intramandibular kinesis (37-45).— The progressive development of intraman- 
dibular kinesis figured prominently in McDowell and Bogert's characterization of Va- 
ranoidea, and also has been discussed by Rieppel (1980a) and Gauthier (1982). In these 
and other studies several characters affecting mandibular kinesis have been identified: 
a truncated margin of the posterolateral edge of the dentary; surangular foreshortened 
anteriorly; splenial reduced anteriorly and posteriorly; anterior extension of the lateral 
and medial arms of the coronoid present, but not broadly overlapping the dentary; a 
tiny, free posteroventral process on the intramandibular septum (IMS); and a fibrous 
connection between the dentary and postdentary bones. These modifications appear to 
form a developmentally and functionally related complex of characters that distinguish 
the mandible of varanoids from all other anguimorph squamates. That is, there is at 
least some mobihty of the dentary with respect to the post-dentary bones. 

McDowell and Bogert (1954:108) believed that the principal modification in the 
evolution of intramandibular kinesis was the formation of a vertically truncated pos- 
terior margin of the dentary, such that the dentary overlaps little or not at all with the 



171 



post-dentary bones. In helodermatids, they thought (incorrectly) that the intramandib- 
ular hinge was absent (//. suspectum) or rudimentary (//. horridum) because the pos- 
terolateral edge of the dentary is not truncated in these species, the structure being 
more like the primitive anguimorph condition in having an obvious surangular notch 
at the posterolateral edge (Gauthier 1982). However, manipulation of freshly excised 
mandibles of both species of Heloderma demonstrated to us that the dentary can move 
freely through an arc of approximately 1 0° with respect to the post-dentary bones; 
similarly, the dentary of Varanus prasinus can be moved through an arc of approxi- 
mately 17°. The splenial passes posterior to this joint in Heloderma. However, the 
splenial is quite thin and it simply bends during kinesis. By contrast, in varanines, and 
presumably lanthanotines, the splenial moves as a unit with the dentary. A vertically 
truncated posterolateral margin of the dentary (and splenial) is, therefore, not required 
for kinesis, although it apparently enhances mobility. 

Our dissections indicate that the internal structure of the mandible at the coronoid 
juncture probably plays the most important role in facilitating movement in the lower 
jaw. In anguids and xenosaurids the surangular is long, tapers anteriorly and terminates 
inside the dentary well forward of the last tooth, as in most squamates (Gauthier 1982). 
The surangular bone is recessed laterally to receive a prominent overlapping portion 
of the dentary. Thus, a broad mutual overlap between the dentary and postdentary 
bones prevents flexure at the coronoid juncture. In varanoids, however, the surangular 
is not tapered, and the anterior end is truncated so that it barely reaches the posterior 
end of the tooth row. Accordingly, overlap between the dentary and surangular is 
restricted; the bones are secured to one another by a thick band of connective tissue 
rather than by the firm osseous connection seen generally in anguids, xenosaurids, and 
other squamates (Gauthier 1982). 

Another feature of the mandible of some varanoids is the presence of a small notch 
in the posteroventral margin of the intramandibular septum (IMS). The anteroventral 
end of the surangular fits into this notch, thus restricting torque about the intraman- 
dibular joint. In Varanidae and some Heloderma suspectum this character has reversed, 
the notch being absent. 

Preliminary developmental studies suggest that there are few neomorphic structures 
in the mandible of varanoids that promote kinesis; rather the action is accomplished 
by an apparently paedomorphic reduction in the extent of contact among the bones 
comprising the dentary/post-dentary articulation, as well as an incorporation of fibrous 
connective tissue into this joint. 

D. Maxillary tooth row not extending posteriorly below orbit {11); ectopterygoid 
elongate and contacting palatine to exclude maxilla from suborbital fenestra (36). 

E. Bases of teeth expanded and infolded (plicidentine) (24); teeth sharply pointed, 
trenchant, recurved and widely-spaced (25); teeth without replacement pits, i.e., teeth 
develop outside tooth bases (26) {see also Rieppel 1978). 

F. Partial retraction of nares, i.e., nasals barely or not at all in contact with pre- 
frontals (2,3,4). -McDowell and Bogert (1954) characterized helodermatids and all 
other platynotans as having retracted nares. That is, the external nares are elongated 
posteriorly such that they separate the nasal from the prefrontal and maxilla. Appar- 
ently, they based their conclusion regarding Heloderma on a specimen of H. horridum 
(AMNH 57863) that was also illustrated in their monograph (p. 36). This same illus- 
tration and the character itself was used later by Bogert and Martin del Campo (1956: 
1 8). Rieppel ( 1 980<3) also included this feature as a character of Varanoidea. On AMNH 
57863 the osteoderms had been removed from the left side of the skull to reveal a 
narrow slit in the posterodorsal end of the bony nares between the nasal, maxilla, 
prefrontal and part of the frontal, giving the appearance of "retracted" nares. However, 
in Heloderma extensive connective tissue occurs in the nasal-maxilla-prefrontal region 
that usually shrinks when the skull is prepared as a dry specimen. Depending on the 
degree of desiccation, the nasal bone can show varying degrees of separation from the 
maxilla and prefrontal. This appears to be the case with AMNH 57863. These bones 
have smooth narial margins in varanids and form true retracted nares: there is no 



172 



contact between the nasal and maxilla, and very little {Lanthanotus) or none (all other 
varanids) between the nasal and prefrontal. Anguids and xenosaurids exhibit broad 
contact of the nasal with the maxilla, but very little occurs in Heloderma. Heloderma 
does possess a broad nasal-prefrontal contact, as seen generally in squamates. Thus, 
moderately retracted nares occur in Heloderma by an anterior narrowing of the nasals, 
although the bones are not as reduced in length as they appear in Lanthanotus and 
Varanus. 

Miller (1966): 

G. Cochlear duct robust and broad, limbus elongate and heavily constructed (75). 

Lecuru (1968a, b): 

H. Mesosternum absent (60). 

I. Anterior process of interclavicle reduced or absent (59).— An anterior process of 
the interclavicle is absent in some species of Varanus (e.g., V. niloticus) but a short 
process is present in others (e.g., V. griseus; also Saniwa— personal observation). Lecuru 
(l96Sa) and Rieppel (1980Z?) present conflicting evidence for Lanthanotus. Lecuru 
( 1 968a: fig. 1 5) illustrated the interclavicle having a pair of horn-like anterior processes, 
whereas Rieppel (1980b: 103) figured the structure without any sort of anterior process, 
the crossbar or lateral processes being a rectangular plate at the anterior end of the 
bone. In this respect, our specimen of Lanthantus (REE 1445) agrees with that figured 
by Lecuru. 

J. Clavicles gracile (58). 

K. Ulnar nerve passes deep in forearm ("varanid condition") (76) {see Renous- 
Lecuru 1973). 

Hoffstetter and Gasc (1969): 

L. Vertebrae with precondylar constriction (not listed).— Precondylar constriction 
of the trunk vertebrae is marked in Varanus, and hardly noticeable in Heloderma. In 
fact, McDowell and Bogert (1954) claimed that in Heloderma the vertebrae were not 
constricted anterior to the condyles. Rieppel ( 1 980Z)) reported that Lanthanotus exhibits 
a condition very similar to that of Heloderma, wherein the precondylar constriction is 
present, but faint. Actually, this character can only be evaluated subjectively and we 
prefer not to consider it diagnostic of Varanoidea; undoubtedly it is a synapomorphy 
of Varanus. 

M. Peduncles on cervical and caudal vertebrae supporting hypapophyses and chev- 
rons, respectively (53, 54). — In following Hoffstetter and Gasc (1969) and his own 
observations, Rieppel (1980Z)) recorded the presence of cervical and caudal peduncles 
as a synapomorphy of Varanus and Lanthanotus. On the other hand, McDowell and 
Bogert (1954:124) stated that "Even the most primitive platynotan [Heloderma] has 
distinct pedicles for the caudal chevrons, as far as known, all platynotans have the 
chevrons freely articulated to the caudal centra." We concur with McDowell and Bogert. 
Whereas caudal peduncles are certainly most prominent on Varanus, they are not 
unique. They are present, albeit feebly, on our comparative skeletons of Heloderma, 
and in fact can be observed in other anguimorphs, such as Xenosaurus. The hyper- 
developed cervical and caudal peduncles of varanids, and the fact that neither the 
chevrons nor the cervical intercentra contact the centrum condyle, will distinguish this 
taxon, but the presence of caudal peduncles themselves will not diagnose Varanoidea. 

Saint Girons (1976): 

N. Large, anatomically differentiated sero- mucous gland on lower jaw [Gland of 
Gabe (Kochva 1974)] (73). 

O. Calyciform duodenal cells of muco- serous rather than mucous type (74). 



173 

Gabe and Saint Girons (1976): 
P. Double lacrimal canal (80). 

Rieppel (1980a. b): 

Q. Epicoracoid does not contact the suprascapula and mesoscapula to enclose a 
scapular fenestra (55) (also Camp 1923). 

R. Narrow-based bodenaponeurosis attached to caudomesial edge of coronoid pro- 
cess (except LanthanotuSy) (69). 

S. Insertion of M. episterno-cleido-mastoideus reaches supratemporal process of 
parietal (62). 

T. M. adductor mandibulae externus profundus (3b-layer) originates from supra- 
temporal only (64). 

U. Origin ofM. geniomyoideus is deep to M. genioglossus medialis (65). — In Lan- 
thanotus the origin of the M. geniomyoideus is superficial relative to the M. genioglossus 
medialus, as in all xenosaurids and anguids; therefore the condition appears ancestral. 
In Varanus, however, the muscle has shifted its origin and is entirely deep to the M. 
genioglossus medialis. In Heloderma the origin is transitional in that some fibers still 
retain an attachment with the symphyseal tip of the dentary, whereas others are deep 
to the M. genioglossus medialis (Rieppel 1980a). We consider the condition in Lan- 
thanotus secondary in this regard. 

V. Insertion ofM. levator pterygoidii does not extend posteriorly beyond columellar 
fossa of pterygoid (67).— Also in Heloderma suspectum, but not H. horridum; alter- 
natively, H. suspectum and Varanidae may have acquired this condition separately. 

W. Vomers with distinct palatal shelves (32).— The vomers are narrow, elongate 
structures only in Heloderma and Varanus, i.e., distinct palatal shelves are absent. 
Ancestrally, the vomers are broad as in Lanthanotus borneensis. However, in this species 
attainment of broad palatal shelves is probably a character reversal, judging from the 
narrow and elongate vomers exhibited by the late Cretaceous lanthanotine, Cherminotus 
longifrons {see Borsuk-Bialynicka 1984). 

X. Odontoid sutured and not fused to axis (not listed, see Y). 

Y. Second intercentrum sutured and not fused to axis (not listed).— The unfused 
odontoid and second intercentrum are size and age related characters (Gauthier 1982). 
These structures fuse to the axis in large, older individuals (e.g., Varanus salvator 
SDSNH 57080), as they do in all lepidosaurs. 

This Paper: 

Z. Vomers more than twice as long as palatines (3 1 ); palatines approximately as 
wide as /o«^ (3 3).— Although the form of the snout differs among these taxa, the vomers 
of helodermatids, and varanids are elongate, being nearly twice the length of the pal- 
atines. This condition is diagnostic of varanoids among anguimorphs, and among 
squamates generally. Elongate vomers may be associated with the transverse ptery- 
gopalatine suture, which has been interpreted as a functional response to over retraction 
of the hypokinetic axis (Borsuk-Bialynicka 1984). Concomitantly, the palatines and 
anterior ends of the pterygoids are shortened with respect to the vomers. In Recent 
Heloderma we note that the vomerine process of the palatine is further reduced such 
that it does not extend anteriorly beyond the level of the last maxillary tooth. 

Elongate vomers also are characteristic of certain late Cretaceous anguimorphs 
from Mongolia shown in the plates and figures in Borsuk-Bialynicka (1984: figs. 2, 8, 
1 1; plates 1, 5). They occur in Gobiderma pulchrum, perhaps Paravaranus angusitfrons, 
and Proplatynotia longirostrata. Thus, the character may be applicable at a taxonomic 
level more inclusive than Varanoidea, as constituted here. 

AA. Premaxillary teeth abruptly smaller than maxillary teeth (23). 

BB. Supratemporal bone reaches level of parietal notch (apex of angle formed by 



174 





Figure 1 . Lateral view of left maxilla of Heloderma (top) and Varnaus showing the derived, posterior 
position of the nasal process in the latter. 



supratemporal processes) (19).— In varanoids the supratemporal is longer than in other 
Anguimorpha; it reaches anteriorly level with the apex of the parietal notch. This 
character may be associated with the 3b-layer of the MAME profundus (T, above), 
which takes its origin soley from this bone in varanoids, whereas in other anguimorphs 
it invades the descensus parietalis to varying degrees. Rieppel (1980a) considered that 
the varanoid condition of the muscle is primitive with respect to other squamates, 
although he used it as a diagnostic feature. Hence, a long supratemporal might also 
represent an ancestral condition. Our inspection of other anguimorphs brought mixed 
results; most have a short supratemporal relative to its distance from the parietal notch. 
Thus, the origin of the MAME profundus and the length of the supratemporal may be 
a synapomorphy of varanoids, and we believe that the consequent restriction of the 
MAME profunds to the supratemporal might therefore be a redundant character. 

Synapomorphies of Varanidae (Varaninae + Lanthanotinae) 

ThCi are a number of characters within Varanoidea that designate varanines and 
lanthanoti is as monophyletic and the sister group of helodermatids. Many of these 



175 

were first noted by McDowell and Bogert (1954). Rieppel (1980a, b) has reviewed the 
literature on alternative interpretations, favoring those with a phylogenetic emphasis. 
Based on head musculature (Rieppel 1980a) and the postcranial skeleton (Rieppel 
\9S0b), he concluded, as have others before him, that Lanthanotus is phylogenetically 
closer to Varanus than it is to Heloderma 

The following is a compilation of characters shared between Lanthanotus and 
Varanus that have been considered derived; they are not found in Heloderma, or in 
squamates generally. The number in parentheses refers to the corresponding character(s) 
in Tables 2 and 3. 

McDowell and Bogert (1954): 

A. Nasals fused (1). — Borsuk-Bialynicka (1984) stated that the nasals might be 
paired in the early lanthanotine Cherminotus; however, photographs of the holotype 
(the best preserved specimen) reveal that the condition of the nasals cannot be deter- 
mined with certainty. 

B. Fully retracted nares (2, 4, and see F above). 

C. Nasal process of maxilla rises from a posterior position on that bone (5). In 
helodermatids the nasal process of the maxilla is located in the middle of the maxilla 
(Fig. 1), the ancestral condition in anguimorphs. In Varanus and Lanthanotus the nasal 
process is positioned posteriorly as a result of elongation of the premaxillary process 
and reduction of the orbital process of the maxilla. This feature probably occurs in 
conjunction with fully retracted nares. 

D. Well-developed subolfactory processes directed posteromedially that closely ap- 
proach one another, or contact midventrally (9) (Fig. 2). 

E. Supraoccipital makes broad contact with /7ar/>/a/ (1 5). — Rieppel ( 1 980(3) further 
emphasized this synapomorphy. By contrast, Borsuk-Bialynicka (1984) regarded broad 
parietal contact as convergent, a response to reduced metakinesis in skulls of different 
proportions. Although possibly unrelated, we add (1 8) that the supratemporal processes 
of the parietal are very compressed mesolaterally in Varanus and Lanthanotus, and 
not so in other anguimorphs. 

F. Hypoglossal foramen enlarged, confluent with vagal foramen (16). 

G. Double posterior lacrimal foramen (22).— Two lacrimal ducts are present in 
Heloderma, Lanthanotus, and Varanus (P, above), whereas the duct is single in all 
other lepidosaurs (Gabe and Saint Girons 1976). There is, however, only a single 
posterior and anterior lacrimal foramen in Heloderma, but there are two posterior 
foramina in varanids. The anterior foramen is single in Saniwa and Lanthanotus 
(personal observation), and double in Varanus. 

H. Increased intramandibular kinesis (37-45, and see C above). 
I. Osteoderms, when present, reduced, not fused to skull. (48). 
J. Reduction of the outer conch of the quadrate (20). 

Hoffstetter and Gasc (1969): 

K. Nine cervical vertebrae (49); well-developed cervical and caudal peduncles (53); 
caudal chevrons do not contact centra condyles (54).— Table 1 provides additional 
meristic data on the varanoid axial skeleton. 

Lecuru (1968); Rieppel (1980Z?): 

L. Posterior coracoid emargination present (57).— The presence of a posterior cor- 
acoid emargination is variable in Lanthanotus; see the conflicting descriptions of Lecuru 
(emargination absent) and Rieppel (present, but small). Our specimen of Lanthanotus 
is like Lecuru's in that no posterior coracoid emargination is present. It is also absent 
in Saniwa {personal observation). 

M. Fewer than four phalanges on pedal digit V (not listed). — Rieppel (1980/)) 
considered the loss of a phalanx in pedal digit V an apomorphic condition shared by 



176 







Figure 2. Frontal bones of Heloderma (top), Lanthanotus (middle), and Varanus (bottom). Ventral view 
(right) shows orientation of the subolfactory processes (anterior in Heloderma). 



177 
Table 1. Meristic characters of the varanoid axial skeleton. 





Heloderma 


Lanthanotus 


Varanus 


No. cervical vert. 


8 


9 


9 


1st cervical rib 


V4 


V4 


V5-7 


No. presac. vert. 


32-36 


35 


29 


No. lumbar ribs 


3-4 


3 


5 


No. true lumbar vert. 


2 


1 


1 


No. caudal vert. 


25-40 


63-69 


60-110 


1 St caudal chevron 


V2(3) 


V2 


V2 



Heloderma and Lanthanotus. We confirm that only three phalanges are present in 
Lanthanotus, but all H. suspectum and at least some H. horridum at our disposal have 
the ancestral condition of four phalanges on the fifth pedal digit. Of seven H. horridum 
from the same brood bom in the Detroit Zoo, four of these had four phalanges on the 
fifth pedal digit and three had three. We consider the variable number diagnostic of 
H. horridum among Heloderma. 

Rieppel (1980a): 

N. Articular socket present on dorsal surface of cephalic condyle of quadrate to 
receive squamosal peg (not listed).— We note the presence of this socket in large indi- 
viduals of Heloderma and its absence in small Varanus. It may, therefore, be a size 
related character; more important, the peg and socket articulation appears to be a basic 
squamate character, as described by Robinson (1967). 

O. M. constrictor colli extends anteriorly covering first ceratobranchials (63). 

P. M. genioglossus lateralis subdivided into separate bundles (66). 

Q. Anterior head of M. pseudotemporalis profundus enlarged (68). 

Branch (1982): 

R. Hemipeneal morphology, viz., paired horns develop as extensions of the main 
retractor muscle (70). — In a recent examination of cloacal and hemipenial musculature 
of lizards, Arnold (1984), not citing Branch (1982), described a combination of derived 
characteristics for Varaninae. He (Arnold 1984:75) concluded, "but, as these are not 
shared with the other two surviving platynotan families, which approach the generalized 
lizard condition, they provide no evidence of relationships among these groups." Ar- 
nold's assessment may not be in contradiction of Branch (1982), who apparently was 
referring to cartilage-like conical horns penetrating the hemipenal lumen in Lanthanotus 
and Varanus. We retain this character as a synapomorphy of Varanidae. 

Gauthier(1982): 

S. Surangular does not extend anteriorly far beyond coronoid eminence (40). 
T. Coronoid and surangular processes on posterolateral margin ofdentary reduced 
(38). 

U. Intramandibular septum without posteroventral notch (41). 
V. Splenial moves with dentary (44). 

Schwenk (MS): 

W. Foretongue notched for at least 40% of length (72). 

Estes, de Queiroz, and Gauthier (MS): 

X. Second epibranchial absent {11). 

Y, Three or fewer pairs of sternal rib attachments (61). 



178 



Convergent Characters within Varanoidea 

Monophyly of Varanoidea, composed of Helodermatidae, Lanthanotinae and Var- 
aninae, is supported by 37 synapomorphies (Tables 2 and 3); 26 others unite Lanthano- 
tinae and Varaninae as Varanidae, the sister group of Helodermatidae (Fig. 3). Hel- 
odermatidae is diagnosed by 23 characters {see Part II). Several derived characters, 
therefore, must be regarded as convergent acquisitions between Lanthanotus and Helo- 
derma. 

Heloderma and Lanthanotus are convergent in the following nine derived char- 
acters: frontals trapezoidal (6); prefrontal and postfrontal contact above the orbit (10); 
parietal foramen absent (1 1); absence of upper temporal bar (12 and 1 3); rounded snout 
(21); and more than 30 presacral vertebrae (51). Estes et al. (MS) also note that Lan- 
thanotus and Heloderma have acquired independently the absence of an ossified pal- 
pebral (78), and a reduced number of scleral ossicles (79). 

Convergence in the skull characters is revealed by the early lanthanotine Cher- 
minotus longifrons Borsuk-Bialynicka, which retains the ancestral conditions of some 
of these characters (e.g., characters 6, 10, 11, 12, and 21) by comparison to Lanthanotus 
and Heloderma. Moreover, unlike Lanthanotus, in Cherminotus the parietals are not 
elongate nor are the frontals foreshortened; the splenial is not as short posteriorly; and 
the vomers are narrow. However, it can be identified as a lanthanotine by details of 
skull morphology, in addition to those characters above that Lanthanotus shares (con- 
vergently) with Heloderma. Cherminotus also shares apomorphies with varanines, such 
as external nares that are nearly completely retracted, broad contact of the supraoccipital 
with the parietal, and the absence of fused cephalic osteoderms. 

Discussion of Varanoidea 

Operationally, Varanoidea needs to be placed in a framework with necrosaurids 
and other extinct "platynotans." Unfortunately, the state of preservation of most nec- 
rosaurian taxa is insufficient for more than a provisional diagnosis of the group. More- 
over, necrosaurids are characterized primarily by ancestral features. Although they 
display some unusual combinations of ancestral anguimorph and varanoid characters, 
only the condition of fused frontal bones in some adult necrosaurids could be considered 
diagnostic. The shape of the parietal, maxilla and teeth, as well as features of the 
mandible indicating limited kinesis, suggest that these early and generalized angui- 
morphs are related to varanoids. However, necrosaurids lack well-developed subol- 
factory processes below the frontals, at least in the better preserved specimens. Likewise, 
the external nares are only weakly retracted, and in some there is only incipient infolding 
of the tooth bases (Borsuk-Bialynicka 1984, Estes 1983<2). Osteoscutes may be rhom- 
boid, polygonal or oval, fused to the skull roof or free (Estes 1983). At this time, 
necrosaurids, as Estes (1983) hypothesized, are probably best understood as being a 
collection of fairly generalized platynotans. 

Borsuk-Bialynicka (1984) has evaluated Platynota in the context of a polyphyletic 
origin from various members of a "necrosaurian stock." She recognized a polyphyletic 
grade "modem Platynota" that consists of Varanidae, Lanthanotidae, Helodermatidae 
and Mosasuridae. This group is identified by those classical characters used by previous 
workers: 1) a high degree of intramandibular kinesis (less so in Helodermatidae); 2) 
strong development of the subolfactory processes (not in Mosasauridae); 3) teeth with 
prominent basal infolding (less so in Helodermatidae); 4) a transverse pterygopalatine 
suture; 5) retracted external nares (only incipient in Helodermatidae); 6) size increase; 
7) fragmentation of cephalic osteoderms (unknown in mosasaurs). 

Borsuk-Bialynicka (1984) argued from functional considerations of the skull, es- 
pecially with regard to gradual improvement of predatory adaptations (such as mod- 
ifications of the palatal elements). In her scheme, helodermatids were independently 
deriv(?d, and even lanthanotines and varanines were regarded as clades that originated 
separately from "necrosaurs." The host of derived osteological features shared by 



179 



Heloderma 




-6 




-8 




-10 




-11 




-12 




-13 




-14C-3 




-21 




-29 




-30 




-47 




-50 




-51 




-56 




-78 




-79 



Lanthanotus 


— 


-6 


— 


-10 


— 


-11 


— 


-12 


— 


-13 


— 


-21 


— 


-32C-] 


— 


-51 


— 


-69C-] 


— 


-78 


— 


-79 



Varanus 

--34 
--35 
--57 



Varanidae 
1,2,4,5,9,15,16,17 

1 8,20,22,38,40.4 1C-3 

44,48,49,53,54,61 

63,66,68.70,72,77 



Varanoidea 

3,7,14,19,23,24,25,26 

27,28.31.32,33,36,37 

39,41,42,43,45,46,52 

55,58,59.60,62,64,65 

67,69,71,73.74,75,76,80 



Figure 3. The relationships of Varanoidea as determined from character states in Tables 2 and 3. [PAUP: 
93 steps, C.I. = 0.86] 



varanines and lanthanotines (^^^^ above) are believed by Borsuk-Bialynicka to be parallel 
achievements, a conclusion with which we strongly disagree. For example, she believed 
that the broad contact of the supraoccipital with the parietal was a convergent means 
of restricting metakinetic movement, which itself was a response to overall proportions 
of the brain case and snout, these supposedly being different in the two taxa. 

We conclude that monophyly of Recent varanoids and varanids are highly cor- 
roborated hypotheses. A phylogeny envisioning a polyphyletic origin implies only that 
considerable work remains to be done in character analysis of "Necrosauridae." Dol- 
ichosauridae, "Aigialosauridae" and Mosasauridae. It is safe to say that by the late 
Cretaceous Helodermatidae was represented by Paraderma, Lanthanotinae by Cher- 
minotus, and Varaninae by Saniwides and Telmasaurus (Estes 1983a, Borsuk-Bialyn- 
icka 1984). For now, we are inclined towards a conservative interpretation, as suggested 
by Rieppel (1980a, b), that would recognize the monophyly of Varanoidea as a group 
restricted to Helodermatidae, Lanthanotinae and Varaninae. The name "Platynota" 
may be retained for convenience as it was applied by McDowell and Bogert, and by 



180 



Table 2. Character summary of Varanoidea, arranged in anatomical sequence, and scored as ancestral (0) 
or derived (1). Those preceded by "v" are diagnostic of Varanoidea. See Table 3 for character state 
distribution. 

Skull characters 

1. Nasal bones paired (0), or fused (1). 

2. Nasal and prefrontal bones in broad contact (0), or with little or no contact (1). 
3.V Nasal and maxillary bones in broad contact (0), or with little or no contact (1). 

4. Nasals and maxillary bones in narrow contact (0), or not in contact (1). 

5. Nasal process of maxilla rises from the middle (0), or posterior (1) aspect of maxillary. 

6. Frontal more or less parallel-sided (0), or trapezoidal (1). 

7.V Subolfactory processes of frontals short, not in contact ventromedially (0), or well-developed and 
closely opposed or contacting ventromedially (1). 

8. Subolfactory processes of frontals do not descend to contact each other anteromedially (0), or do 

so(l). 

9. Subolfactory processes of frontal do not descend to approach or contact each other posteromedially 

(0), or do so (1). 

10. Prefrontal does not (0), or does closely approach or contact postfrontal above orbit (1). 

1 1. Parietal foramen present (0), or absent (1). 

12. Postorbital present (0), or absent (1). 

13. Squamosal large, extending to postorbital (0), or small and reduced (1). 
14.V Temporal musculature inserts ventrally (0), or dorsally (1) on parietal table. 

15. Supraoccipital not in broad contact with parietal (0), or with broad contact (1). 

16. Hypoglossal foramen not enlarged (0), or enlarged (confluent with vagal foramen) (1). 

17. Carotid duct present (0), or absent (1). 

18. Supratemporal process of parietal broad in dorsal aspect (0), or narrow (1). 

19.V Supratemporal bone does not reach level of apex of parietal notch (0), or does (1). 

20. Quadrate with large outer conch (0), or conch reduced ( 1 ). 

21. Muzzle tapered, narrowing anteriorly (0), or blunt and rounded (1). 

22. Posterior lacrimal foramen single (0), or double (1). 

23. V Premaxillary teeth large (0), or abruptly smaller than maxillary teeth (1). 

24. V Plicidentine teeth absent (0), or present (1). 

25. V Teeth bluntly pointed (0), or sharply pointed, trenchent, recurved, and widely-spaced (1). 

26. V Successional replacement teeth in resorption pits (0), or replacement teeth develop posteriorly, no 

resorption pits present (1). 

27. V Maxillary tooth row extends posteriad of orbit (0), or is entirely antorbital (1). 

28. V Maxillary teeth number 13 or more (0), or less than 13 (1). 

29. Maxillary teeth greater than 9 (0), or less than/equal 9(1). 

30. Venom groove absent (0), or present (1). 

31.V Vomer short (0), or nearly twice the length of palatine (1). 

32. V Palatal shelves of vomer wide (0), or narrow (1). 

33. V Palatine longer than wide (0), or equally wide as long (1). 

34. Palatine teeth present (0), or absent (1). 

35. Pterygoid teeth present (0), or absent (1). 

36. V Ectopterygoid does not contact palatine anteriorly (0), or does to exclude maxilla from suborbital 

fenestra (1). 

37. V Dentary and surangular overlap considerably (0), or very little (1). 

38. Coronoid and surangular proceses of dentary well-developed (0), or processes reduced (1). 

39. V Surangular tapered anteriorly (0), or blunt and expanded anterodorsally (1). 

40. Surangular extends well beyond coronoid eminence (0), or does not (1). 

41.V Intramandibular septum (IMS) without posteroventral notch (0), or notched (1). 

42. V Splenial extends posterior of coronoid eminence (0), or does not (1). 

43. V Splenial-dentary suture firm (0), or loose, with much connective tissue between the two bones (1). 

44. Splenial does not move with dentary (0), or does (1) 

45. V Coronoid without long anterolateral and anteromedial proceses (0), or processes present (1). 

46. V Head scales large and plate-like (0), or partly or completely fragmented (1). 

47. Osteoderms thin, plate-like (0), or rounded and thick (1) 

48. Osteoderms fused to skull (0), or not (1). 

Axial characters 

49. Number of cervical vertebrae eight (0), or nine (1). 

50. Vertebral centra long and neural spines broad (0), or centra short and neural spines narrow and 

tall (1). 

51. Number of presacral vertebrae fewer than 30 (0), or more (1). 
52. V Caudal vertebrae autotomic (0), or not (1). 

53. Peduncles on cervical and caudal vertebrae short (0), or long (1). 

54. Caudal chevrons and cervical hypapophyses (=intercenta) contact centrum condyle (0), or on 

centrum only (1). 



181 



Table 2. Continued. 



Appendicular characters 

55.V Epicoracoid contacts suprascapula and mesoscapula (0), or not (1). 

56. Anterior coracoid emargination present (0), or absent (1). 

57. Posterior coracoid emargination absent (0), or present (1). 

58. V Clavicle loop-shaped medially (0), or gracile and not expanded (1). 

59. V Interclavicle with long anterior process (0), or process short or absent (1). 

60. V Mesostemum present (0), or absent (1). 

61. Rib attachments on sternum more than three pairs (0), or three or fewer pairs (1). 

Myological characters 
62. V M. epistemo-cleido-mastoideus does not reach parietal (0), or has extensive insertion on parietal 

(1). 
63. M. constrictor colli does not cover 1st ceratobranchials (0), or does (1). 
64. V Origin of MAME profundus from supratemporal and parietal (0), or supratemporal only (1) [may 

be redundant with 19, see text]. 
65. V Insertion of M. geniomyoideus is completely superficial to M. genioglossus medialis (0), or insertion 

is at least partly deep to M. genioglossus medialis (1). 
66. M. genioglossus lateralis single (0), or subdivided into separate bundles (1). 
67. V? Insertion of M. levator pterygoidii extends posteriorly beyond columellar fossa of pterygoid (0), or 

does not (1). 
68. Anterior head of M. pseudotemporalis profundus not enlarged (0), or enlarged (1). 
69. V? Bodenaponeurosis with broad base (0), or narrow base attached only to caudomesial edge of coronoid 

(1). 
Other characters 

70. Hemipenis without paired horns as extensions of main retractor muscles (0), or with them (1). 

71.V Foretongue not deeply cleft (0), or deeply cleft (not less than 20% of length) (1). 

72. Foretongue cleft for 20% of length or less (0), or not less than 40% of length (1). 

73. V Gland of Gabe absent (0), or present (1). 

74. V Calyciform duodenal cells simple (0), or sero-mucous type (1). 

75. V Cochlear duct not robust (0), or robust and broad, limbus elongate and heavy (1). 

76. V Ulnar nerve superficial (0), or deep (1) in forearm. 

77. Second epibranchial present (0), or absent. 

78. Ossified palpebrals present (0), or absent (1). 

79. Scleral ossicles 14 (0), or fewer (1). 
80. V Lacrimal duct single (0), or double (1). 



Rieppel, but with the understanding that the monophyly of that group has not yet been 
established. 

II. Systematic Account of Helodermatidae 

In this section we describe new fossils of helodermatids, and provide a systematic 
review of the taxa assigned. Our decisions on character state polarity are based on the 
foregoing assessment of varanoid characters and relationships. 

Amniota 

Squamata 

Autarchoglossa 

Anguimorpha 

Varanoidea 

Helodermatidae 

Lowesaunis, new taxon 

Figures 4-6 

Type species.— Heloderma matthewi GWvaovQ, 1928. 

Diagnosis.— A taxon distinct from other Helodermatidae in possessing triangular 
frontal bones, as opposed to trapezoidal. 

Etymology.— The name honors Charles H. Lowe, Professor of Biological Sciences 
at the University of Arizona, in recognition of his extensive contributions to the ecology 
of western North America. 



182 



Table 3. Distribution of varanoid character states from Table 2 (1 = derived, = ancestral, 9 = missing 
data); a phylogeny is shown as Fig. 3. 





"Necrosauridae" 


Heloderma Lanthanotus Varanus 


Character: 








1. 





1 


1 


2. 





1 


1 


3. 





1 1 


1 


4. 





1 


1 


5. 


0/1 


1 


1 


6. 










7. 







1 


8. 










9. 





1 


1 


10. 










11. 










12. 


9/0 







13. 


9/0 







14. 


1 


1 




15. 





1 




16. 


9 


1 




17. 


9 


1 




18. 





1 




19. 


9 


1 1 




20. 


9 


1 




21. 





1 1 





22. 


9 


1 




23. 


1 


1 1 




24. 


1/0 


1 1 




25. 


1 


1 1 




26. 


0/1 


1 1 




27. 


1/0 


1 1 




28. 





1 1 




29. 





1 




30. 





1 




31. 


1 


1 1 




32. 


1 


1/9 




33. 





1 1 




34. 










35. 










36. 


0/1 


1 1 




37. 


9 


1 1 




38. 





1 




39. 


9 


1 1 




40. 





1 




41. 


1 


1/0 




42. 


1 


1 1 




43. 


9 


1 1 




44. 


9 


1 




45. 


1 


1 1 




46. 


1 


1 1 




47. 





1 




48. 


0/1 


1 




49. 


9 


1 




50. 





1 




51. 





1 1 




52. 


9 


1 1 




53. 


9 


1 




54. 


0? 


1 




55. 


9 


1 1 




56. 


9 


1 





57. 


9 







58. 


9 


1 1 




59. 


9 


9 1? 




60. 


9 


1 1 




61. 


9 


1 





183 



Table 3. Continued. 





"Necrosauridac" 


Heloderma 


Lanthanolus 


Varanus 




62. 


9 


1 


1 






63. 


9 





1 






64. 


9 













65. 


9 


1 









66. 


9 











67. 


9 


1/0 








68. 


9 











69. 


9 


1 









70. 


9 











71. 


9 


1 








72. 


9 











73. 


9 


1 








74. 


9 


1 








75. 


9 


1 








76. 


9 


1 








77. 


9 











78. 





1 









79. 


9 


1 









80. 


9 


1 




1 





Lowesaurus matthewi (Gilmore) 

Synonym.— Heloderma matthewi Gilmore. 

Holotype.—AMNYl 990A, posterior part of left maxilla with three teeth. 

Type locality. —Lev/is Creek, Logan County, Colorado. 

Previously referred specimens.— KUVP 7652, maxilla, Middle Oligocene, White 
River Formation, Logan Co., Colorado; UNSM 50011, partial skull represented by 
right maxilla, frontal, partial parietal, partial right jugal, right postfrontal, partial right 
pterygoid, partial right prefrontal, partial basisphenoid, supraoccipital, partial quadrate, 
isolated osteoscutes and a partial right dentary; Late Oligocene (Whitneyan), Brule 
Member, White River Formation, Morrill Co., Nebraska (Gilmore 1928, Yatkola 1976). 

New material (this paper). — KUVP 49651, a nearly complete right frontal bone; 
KUVP 49652, two trunk vertebrae. 

Locality and horizon (new material). — Redington Gap SW'/2, SE'A, Sec. 14, T. 19n., 
R.52W., 3V2 miles south and 9'/2 miles west of Bridgeport, Morrill County, Nebraska. 
Mitchell Pass Member, Gering Formation, Arikaree group (early Miocene; approxi- 
mately 25-27 mybp). 

Description of new material.— The frontal bone (KUVP 49651) tapers anteriorly 
giving it a distinctive triangular outline (Fig. 4). It measures 16.6 mm and 7.8 mm 
along the medial and parietal borders, respectively. Articular surfaces for the pre- and 
postfrontal bones are clearly visible on the lateral margin, where they approach but 
not quite meet each other above the orbital rim. A scar marking the nasal overlap 
extends posterolaterally to the prefrontal suture. Dorsally, the bone is covered with 
polygonal osteoderms that presumably would have conformed to the shape of the 
epidermal scales. The osteoderms are irregular; they are shaped like flattened domes 
separated from one another by moderately deep grooves. Most have a granular texture, 
although the larger ones display tubercles and pits. 

On the ventral surface, the robust subolfactory process is broken distally, and we 
cannot determine with certainty that it would have sutured midventrally with its coun- 
terpart from the left frontal, as happens in Heloderma (Fig. 2). The basal portion of 
the subolfactory process is concave and penetrated by two foramina at the center of 
the concavity. 

Of the two referred vertebrae (KUVP 49652), one is missing the distal extent of 
each zygapophysis (Fig. 5). All that remains of the other is the centrum. The more 



184 





Figure 4. Lowesaurus matthewi (gen. nov.) right frontal (KUVP 4965 1) drawn in dorsal (left) and ventral 
(right) views. Approx. x 7. 



complete specimen has a low, square profile not unlike characteristic trunk vertebrae 
of Heloderma. It is 5.8 mm from the inferior margin of the cotyla back to the tip of 
the condyle, and 7.8 mm across the tips of the prezygapophyses. The bone is 5.4 mm 
high measured from the posteroventral edge of the condyle to the top of the neural 
arch; the tip of the neural spine is missing. The lateral borders of the centrum are 
parallel, and the condyle is large, elliptical and preceded by a faint constriction. The 
neural arch is low and slopes gently posterodorsally. 

Remarks.— Y3X\.o\?i (1976:6) illustrated a complete frontal bone articulating with 
a partial parietal (UNSM 5001 1), as part of the material that he referred to H. matthewi. 
Reexamination of this fossil (Fig. 6) and comparison with KUVP 4965 1 in hand shows 
them to be similar in overall shape, position of the articular facets, and robustness of 
the subolfactory processes. KUVP 49651 differs in having slightly larger, higher and 
more tuberculate osteoderms separated by deeper grooves. Certainly the most com- 
pelling feature in common is their triangular shape. 

Ancestrally, the frontal bones of anguimorphs are parallel-sided above the orbits 
and laterally expanded at the anterior and especially posterior ends; the frontal partic- 
ipates broadly in the orbital rim (Gauthier 1982). In helodermatids ancestrally, the 
frontals are trapezoidal, broad above the orbits, and with very little {Lowesaurus) or 
no {Heloderma) participation in the orbital rim owing to the contact of the pre- and 
postfrontal bones. Also important is that the descending subolfactory processes suture 
anteromedially. The triangular frontals of Lowesaurus are thus unusual among angui- 
morphs, the shape being repeated elsewhere only in certain glyptosaurine anguids, for 



185 







Figure 5. Lowesaurus matthewi (gen. nov.) vertebra (KUVP 49652) drawn in A) anterior, B) posterior, C) 
dorsal, and D) ventral views. Approx. x 7. 



example Paraglyptosaurus princeps (Sullivan 1979). In helodermatids, the direction of 
change in shape probably coincides with that seen within glyptosaurines, that is, from 
parallel-sided to trapezoidal to triangular. The frontals of Paraderma bogerti and Eur- 
heloderma gallicum must be found in order to verify this hypothesis. 

A New Helodermatid (Indet. Taxon) from the Latest Paleocene, 
Bighorn Basin, Wyoming 

cf. Eurheloderma 

Bartels (1983) recently described an isolated parietal (UMMP 74619) from the 
latest Paleocene of Wyoming (fig. 5; p. 367). He referred to this specimen as a varanoid 
of "indeterminate family, genus and species" (p. 367). Our examination of the speci- 
men confirms that it is varanoid in that the supratemporal scar anteriorly extends to 
the level of the posterior end of the parietal table. Moreover, the absence of a parietal 
foramen and the insertion of the temporal musculature ventrally on the parietal table 
are derived characters diagnostic of Helodermatidae. The parietal table displays dermal 
rugosities, but the overlying osteoderms did not adhere (indicating a subadult individ- 
ual) and were not preserved with the specimen. The parietal is constricted in the manner 
o^ Eurheloderma {see below), but assignment to that taxon would be premature in view 
of our uncertainty regarding the level at which this attribute appeared in helodermatid 
phylogeny. We list it conferee Eurheloderma merely to indicate the similarity. Beyond 
those diagnostic of Helodermatidae, the fossil reveals no other apomorphies, and we 
leave the taxon unnamed pending the discovery of additional material. 



186 




Figure 6. Lowesaurus matthewi (gen. nov). Dorsal (left) and ventral view (right) of frontal and partial 
parietal (UNSM 5001 1). Approx. x3. 



Morphology of Helodermatidae 

Our generic reassignment of the fossils previously referred to Heloderma matthewi 
implies that two lineages of helodermatid varanoids existed during the middle Tertiary 
of North America: Lowesaurus and Heloderma (represented by H. texanum, Fig. 7). 
Only the latter has persisted to the present. We also believe that Paraderma bogerti is 
an early helodermatid, which would thus extend the temporal range of the group back 
to the late Cretaceous in North America. Derived features discussed below are shared 
by all these taxa, at least where known. 

Teeth and venom delivery.— Tht most unusual feature of helodermatids is their 
dentition. The anterior margin of each tooth is inflected medially to form a groove for 
the conduction of venom. The two living species Heloderma suspectum and H. hor- 
ridum possess deeply infolded, well-developed venom grooves on the anteromedial 
margins of all maxillary and dentary teeth (Fig. 8), and frequently there are shallow 
grooves on the more lateral teeth of the premaxilla. The groove is best expressed on 
the largest teeth, those nearest the middle of the tooth row. In Eurheloderma gallicum 
and Lowesaurus matthewi the groove is not as pronounced as it is in the two Recent 
forms, but it does extend to the distal end of the tooth. The venom groove in H. 
texanum is similar to that in E. gallicum and L. matthewi except for having a wider 
basal opening as in the Recent species. 

There are few teeth well preserved on the jaw elements referred to Paraderma 
bogerti. On the holotype (UCMP 5426 1 ; Fig. 9) the most complete tooth is near the 
middle of the dental row and bears an incipient groove on the anteromedial margin 
near the base. We can only speculate, however, that the groove is a venom-conducting 
precursor. The well-preserved premaxillary teeth of this lizard show no grooves, but 
weakly grooved premaxillary teeth occur only in living helodermatid species. 

In fossils of the early varanoids Palaeosaniwa canadensis, Parasaniwa wyomingen- 
sis, Provaranosaurus acutus, and Necrosaurus cayluxi the trenchant margins of the teeth 
are distinctly delimited from the main shaft of the tooth, leaving what could also be 
interpreted as a precursor of a venom conducting groove. Here it is of interest that 



187 




Figure 7. Stereopairs of Heloderma texanum Stevens (holotype UT 40635-123); skull in dorsal (top) and 
ventral views (bottom). Approx. x 2. 



Saint Girons (1977) and Kochva (1974) noted the presence of a large sero-mucous 
gland on the lower jaw of all varanoids, the Gland of Gabe, which is the venom 
producing organ in Heloderma. Thus, it is not unlikely that the potential for venom 
delivery was present early in the history of varanoid lizards. The desert monitor of 
Pakistan, Varanus griseus, may itself produce toxic secretions according to Gorelov 
(1970), although Kochva (1978) has noted contradictory evidence. In any case, the 



188 





Figure 8. Right dentary of Paraderma bogerti (top, UCMP 49939; x 2), and Heloderma honidum (bottom, 
SDSNH 59469; x4.5). 



capability for venom injection was elaborated only within the more derived Helo- 
dermatidae, and as discussed in Part III, probably plays an important role in feeding. 
Characteristic of varanoids, Helodermatidae have a reduced tooth count by com- 
parison with other Anguimorpha. The number of teeth has decreased within helo- 
dermatid phylogeny as well. Eurheloderma gallicum has 11-12 maxillary teeth, and 
12-13 dentary teeth. Lowesaurus matthewi has 1 1 teeth on the maxilla and Heloderma 
texanum has 9 (not 6 as reported by Stevens 1977). The dentary of H. texanum is 
unknown, and only a partial right dentary has been described for Lowesaurus (Yatkola 
1977). Of the two Recent species, H. horridum is thought to possess the fewest number 
of maxillary teeth: 6-7 as opposed to 8-9 in H. suspectum (McDowell and Bogert 1954, 
Bogert and Martin del Campo 1956, Yatkola 1976). Our sample {n = 80) of skeletons 
confirms this only incidentally; the overlap in tooth count is in fact considerable. The 
maxillary tooth count of//, horridum varies from 6-9 with a mean and mode of 7. In 
H. suspectum the range is 7-9 with a mean and mode of 8. In both species, approxi- 
mately one-third of our sample included individuals with a one-tooth count difference 
between left and right jaws. 



189 






Figure 9. Paraderma bogerti. Maxilla (hololype UCMP 54261) in lateral (top) and medial (middle) views; 
premaxilla (bottom, UCMP 54199). Approx. x3. 



The mean and mode of dentary teeth for both species samples is 9. Helodenna 
horridum varies from 8-10, and all individuals of//, suspectum examined had 9 dentary 
teeth except for one, which had 10 teeth on one jaw and 1 1 on the other. 

Maxillary arch.— The maxillary arch of helodermatids is similar to both Lan- 



190 



thanotus and Varanus in that the tooth row is entirely antorbital, a feature emphasized 
by McDowell and Bogert (1954) to distinguish Varanoidea from other Anguimorpha 
{see above). A consequence of the antorbital tooth row in varanoids is that the palatine 
and ectopterygoid contact one another distally to exclude the supradental shelf from 
participating in the suborbital fenestra. This condition is evident in H. texanum and 
appears also to be the case in Eurheloderma and Lowesaurus, to judge from the palatine 
and ectopterygoid articular surfaces on the fossil maxillae. It was probably also the case 
for Paraderma bogerti, but more difficult to discern on this fossil. 

Within Helodermatidae differences exist in the morphology of the maxilla. In the 
early forms Paraderma, Eurheloderma, and Lowesaurus, the dental shelf, indeed the 
entire maxilla, is deeply curved medially. The shelf is essentially straight in Varanus 
and Lanthanotus. In Heloderma texanum the shelf is rather narrow and straight (Fig. 
7), whereas in the two Recent species the shelf is also strongly curved. In these two, 
the anterior end of the shelf widens to form a cup-like depression that isolates the first 
3 or 4 teeth. This depression is scarcely evident in H. texanum, and not at all in 
Eurheloderma or Paraderma. 

Palate. —Teeth are present primitively on the palatal bones (vomer, palatine, pter- 
ygoid) of diapsid amniotes. In general, lepidosaurs have retained palatal dentition 
throughout their evolution, but reduction and loss have occurred independently several 
times, particularly within squamates. Consequently, the absence of palatal teeth is a 
character often difficult to resolve phylogenetically. Within squamates, the loss of palatal 
teeth proceeds from the vomer to the palatine to the pterygoid (Camp 1923, Estes et 
al. MS). Neither modem species of Heloderma retains teeth on the vomer, but in 
contrast to previous reports, teeth may be present or absent on one or both of the 
pterygoids and palatines. On the holotype of//, texanum, a few small teeth are present 
on the palatine, but not on the pterygoid as reported by Stevens (1977). This condition 
is aberrant and may be peculiar to that specimen, or an artifact of preparation or 
fossilization. 

A primitive feature of the palatine of H. texanum is that the vomerine process 
extends anteriorly beyond the level of the penultimate tooth of the maxilla, where it 
articulates with the vomer. This condition also occurs in Varanidea. The derived 
palato vomer articulation is posterior to the level of the last maxillary tooth, as in living 
Heloderma. 

Jugal.— The angle formed by the dorsal and anterior processes of the jugal is less 
acute in Heloderma texanum than it is in //. suspectum and //. horridum. The deflection 
is like that of other anguimorphs, such that the orbits are more oval than round and 
contribute to a lower profile of the skull. The low skull profile of//, texanum could be 
the result of allometry, i.e., the holotype specimen being a subadult {see below). A 
partial right jugal is known for Lowesaurus (UNSM 5001 1), but it is too incomplete 
to reconstruct accurately the shape of the orbit. 

Parietal— In helodermatids the parietal is flat and the adductors take their origin 
from the ventral surface, a derived condition among Varanoidea. The parietal of Low- 
esaurus and Heloderma is broad and trapezoidal, a shape common to all anguimorphs. 
The parietal of Paraderma bogerti is unknown. That of Eurheloderma gallicum is 
markedly constricted just anterior to the diverging supratemporal processes, as in 
UMMP 74619 described above. Yatkola (1976) considered this to be a derived con- 
dition, which may be correct, but the parietal of Paraderma must be found to verify 
the polarity. 

Cephalic osteoderma. — A.\xX2LVc\\og\ossdins primitively have large, plate-like dorsal 
scales that grade into smaller scales anteriorly and laterally. Varanoids are distinguished 
from other anguimorphs by the fragmentation of the large scales and osteoderms on 
the frontal and parietal, except for those of Parasaniwa wyomingensis and Palaeosaniwa 
canadensis, which are like those of anguimorphs ancestrally (Estes 1964, 1983iz). 

As characters, osteoderm size and surface texture are difficult to interpret and 
score. Descriptions are likely to be subjective, and the structures themselves probably 



191 



vary individually, with position on the skull, and ontogenetically. The dilemma is that 
there are precious few other features with which to evaluate many of the fossil taxa. 

In helodermatids the parietal osteoderms are largest in Eurheloderma gallicum, 
smaller in Lowesaurus matthewi, smaller still in Heloderma texanum, and smallest in 
H. suspectum and H. horridum. The maxillary osteoderms are larger than those on the 
frontal in E. gallicum, L. matthewi and H. texanum, but approximately equal in size 
in H. suspectum and H. horridum. 

Within helodermatids, the grooves between adjacent osteoderms deepen with frag- 
mentation and thickening of the osteoderms themselves. They are shallow in P. bogerti, 
E. gallicum, and L. matthewi, deep in H. texanum, and deeper yet in H. suspectum 
and H. horridum. Finally, the surface of the osteoderms is simply vermiculate in P. 
bogerti and E. gallicum, whereas in L. matthewi the surface is mostly vermiculate but 
with tubercles on the largest osteoderms. The osteoderms of H. texanum are mostly 
tuberculate, and pitted and tuberculate in H. suspectum and H. horridum. 

Vertebrae.— The. vertebrae of Paraderma bogerti are unknown, and, except for a 
more constricted vertebral canal, there is little to distinguish those of Lowesaurus 
matthewi from the vertebrae of Eurheloderma gallicum figured by Hoffstetter (1957: 
784). Estes (1963) illustrated a vertebrae from the early Miocene Thomas Farm locality 
of Florida and described it as Heloderma-like, although he referred it to Anguidae; 
subsequently it was placed provisionally with helodermatids (Estes 1983a). By com- 
parison to the Florida specimen, the KUVP vertebra of L. matthewi is half as large, 
and the centrum is not compressed laterally. The vertebra of L. matthewi is larger than 
that of H. texanum, which also has a laterally compressed centrum. 

In Heloderma the trunk vertebrae are short relative to those of Lanthanotus and 
Varanus, and the neural spines are narrower and more acute. There is a modest increase 
in the centrum length of posterior vertebrae of Heloderma, Lanthanotus, and squamates 
generally. Yet, in Varanus the vertebral centra tend to increase in length towards the 
anterior trunk region. 

Body 5zz^.— The modem species of Heloderma are larger than their Tertiary rel- 
atives, assuming that the fossils represent adults of near average maximum size. How- 
ever, for most of the fossil material none of the reliable signs of adulthood and maximum 
size, such as fusion of the epiphyses, basicranial elements, and girdles, are known. 

Stevens (1977) suggested that the relative degree of fusion of osteoderms to the 
skull of//, texanum indicated that the holotype represents an adult. More important to 
us are the unfused sutures on the basicranium and low skull profile, both characteristic 
of a subadult individual. In //. suspectum and //. horridum the head tends to become 
broader in proportion to its length during growth, especially in males (Bogert and Martin 
del Campo 1956). That being the case, allometry may explain the wide angle of the 
jugal and comparatively elongate skull of the H. texanum holotype. We would estimate 
the snout-vent length of that individual at approximately 180 mm, and that of the 
other fossil helodermatids at no more than 250 mm, except one specimen (UCMP 
49939) that may represent P. bogerti, which was at least 800 mm by extrapolation from 
the mandible of Recent Heloderma. 

Bogert and Martin del Campo (1956) listed the average maximum snout-vent 
lengths of H. suspectum and H. horridum at 325 mm and 350 mm, respectively. 
However, two UMMZ specimens of //. horridum are considerably larger (<3 382 mm 
SVL, 2 421 mm SVL), and neither specimen displays all the developmental charac- 
teristics marking cessation of growth. Our sample of skeletons indicates that the dis- 
parity in size between the smaller //. suspectum and the larger //. horridum is consid- 
erably greater than Bogert and Martin del Campo (1956) thought. 

Other characters.— ThQ two living species of Heloderma differ from one another 
in several ways {see part III). The most obvious of these is the proportionately longer 
tail of H. horridum. Bogert and Martin del Campo (1956) noted this difference and 
isolated several characters of this condition: in H. horridum the tail comprises at least 
65 per cent of the snout-vent length; there are 40 instead of 25 to 28 caudal vertebrae; 



192 



and at least 75 rows of subcaudal scales instead of no more than 62. A relatively long 
tail is ancestral among Anguimorpha (see Part III). 

The general color pattern of H. horridum is a mottled dark dorsum and banded 
tail; perhaps cryptic under some circumstances, this pattern is widespread among an- 
guimorph lizards (e.g., Anguidae such as Gerrhonotus, the xenosaurs, and varanids 
such as V. tristis). The more brightly marked, pink and black pattern of H. suspectum 
is derived, perhaps serving biological roles of camouflage, aposematism, or both (Bogert 
and Martin del Campo 1956; see also part III). 

Finally, Heloderma suspectum retains the ancestral state of enlarged preanal scales, 
and four phalanges in pedal digit V. 

Diagnosis of Helodermatidae 

In a strict sense, a diagnosis is a list of a taxon's derived character states (autap- 
omorphies). For Helodermatidae these are given below, and will distinguish this taxon 
from other varanoid lizards; additional descriptive, ancestral features are listed in the 
preceding accounts on varanoid characteristics. 

Our diagnosis also is intended to serve as a means of hypothesizing intrafamilial 
relationships (Fig. 10). Obviously, we must make assumptions about the inclusion of 
referred fossil taxa in the absence of complete knowledge of their anatomy. None of 
these assumptions, however, is inviolate from the standpoint of available evidence. 
Helodermatidae is a taxon of varanoid Anguimorpha with the following attributes: 

1 . Osteoderms thick, hexagonal and covering the entire head and body as a "coat 
of mail." 

2. Skull of robust construction having a steep nasal process of the maxilla, which 
contributes to a rounded muzzle and short face. 

3. Parietal foramen absent. 

4. Gland of Gabe elaborated as a venom producing organ, concomitant with 
grooved teeth on the maxilla and dentary; grooved teeth for venom delivery are best 
developed in the two living species. 

5. Upper temporal arch lost through reduction of the squamosal and loss of 
postorbital (convergent in Lanthanotus). 

6. Participation of frontal in orbit restricted, owing to approach (but not contact) 
of pre- and postfrontals along orbital margin, 

7. Subolfactory processes of the frontal descending anteromedially, joining ven- 
trally in a midline suture. 

8. Maxillary dental shelf curved medially. 

9. Palatines lacking deep choanal grooves (convergent in Varanus). 

10. Palpebral ossification absent (convergent in Lanthanotus). 

1 1 . Pterygoid lappet of quadrate present. 

12. Posterior opening of vidian canal at basisphenoid-prootic suture. 

13. Splenial not extending anteriorly beyond tooth row midpoint. 

14. Scleral ossicles fewer than 14. 

1 5. Innervation of dorsal leg muscles by interosseous nerve [characters 10-15 from 
Estes et al. MS]. 

16. Vertebral neural spines narrow and tall, rising at an acute angle. 

17. Hypapophyses on posterior cervicals reduced (Hoffstetter and Gasc 1969). 

18. Body long (32-36 presacral vertebrae— Table 1). 

19. Tail short (25-40 caudal vertebrae— Table 1). 

20. Interclavicle simple, rod-shaped. 

2 1 . Anterior coracoid emargination absent. 

22. Adductor musculature inserting on the ventral surface of the parietal table. 

23. Diet includes unusually large prey items {see Part III). 

Discussion of Helodermatidae 

The phylogeny of Helodermatidae is depicted in Figure 1 (Table 4); it is nearly 
free of homoplasy (convergence and reversals) and describes a fairly unambiguous 



93 




00 



U 






D 
< 



e 

c9 



CO 

u 

3 



s 

n 

o 
2 

es 
u 

B 

o 



T3 
U 

C 






_o 

ac 

o 

a 
.B 

c 
o 



H 



O 



194 



Table 4. Character summary of Helodermatidae, scored as ancestral (0), or derived (1). Distribution of 
character states is presented in Table 5. 

1. Venom groove absent (0), or present and continuous along tooth margin (1). 

2. Base of venom groove narrow (0), or wider than groove itself (1). 

3. Maxillary dental shelf straight (0), or curved medially (1). 

4. Maxillary dental shelf without anterior depression (0), or expanded and depression present (1). 

5. Maxillary teeth greater than nine (0), or equal/less than nine (1). 

6. Maxillary teeth more than seven (0), or seven (1). 

7. Frontal trapezoidal (not triangular) (0), or triangular (1). 

8. Parietal is not strongly constricted medially (0), or is (1). 

9. Vomerine process of palatine extends anteriad of last maxillary tooth (0), or not (1). 

10. Osteoderms on skull roof wide, separated by shallow grooves (0), or narrow and smaller, separated by 
deep grooves (1). 

1 1 . Osteoderms on maxilla larger than those on frontal (0), or equal to them ( 1 ). 

12. Cephalic osteoderms mostly flat, vermiculate (0), or domed and tuberculate (1). 

13. Caudal vertebrae 40 or more (0), or less than 40 (1). 

14. Enlarged preanal scales present (0), or absent (1). 

15. Color pattern mottled dark, tail banded (0), or pattern bright pink and black, disrupted (1). 

16. Four phalanges on pedal digit V (0), or three or four phalanges (1). 

17. Body size large, at least 350 mm SVL (0), or small; less than 330 mm SVL (1). 

18. Toes long (0), or short (1). 

19. Habitat preference mesic or semimesic (0), or xeric (1). 

20. Insertion of M. levator pterygoidii extends posterior to columellar fossa (0), or not (1). 



hypothesis of phylogenetic relationships. But it also reflects the paucity of fossil material 
and, hence, our assumptions about the origin of certain characters. For example, without 
knowledge of the frontal bone of Eurheloderma we cannot resolve the position of that 
taxon relative to Lowesaurus and Heloderma. Equally, we have assumed that certain 
features of the frontal that specify Helodermatidae do in fact apply to Paraderma, 
where again that structure is unknown. Naturally, the problem of character origin is 
most acute with features of soft anatomy. 

Yatkola (1976:3) stated that "the overall morphologic similarities between E. 
gallicum, H. matthewi, H. suspectum and H. horridum are more impressive than their 
differences. Therefore, I have included all four taxa within the genus Heloderma.^' 
However, we prefer names that indicate monophyly rather than overall similarity. We 
also wish to avoid redundant names, viz., if all taxa are referred to Heloderma then 
there is no need to recognize another name, Helodermatidae, that specifies the same 
taxon. We stated above our reasons for recognition of Lowesaurus, namely the triangular 
frontals (character 7). We also retain Eurheloderma Hoffstetter for the early Cenozoic 
species of France because of the distinctively constricted parietal (character 8). Helo- 
derma is diagnosed by the wide basal opening of the venom groove (character 2) and 
morphologically more robust osteoderms (characters 10, 12). Heloderma texanum is 
primitive with respect to H. horridum and H. suspectum in its absence of: the anterior 
depression of the maxillary shelf (character 4), the foreshortened vomerine process of 
the palatine (character 9), and frontal and maxillary osteoderms of equal size (character 
1 1). Heloderma texanum is derived compared to other helodermatids in possessing a 
straight maxillary dental shelf (reversal, character 3). 

Derived characters of Heloderma suspectum are its bright coloration (character 
1 5), smaller size (character 1 7), short, non-prehensile tail (character 1 3), shorter toes 
(character 1 8), and occupation of xeric habitats (character 1 9). 

Derived characters of Heloderma horridum are its fewer number of maxillary teeth 
(character 6), insertion of the M. levator pterygoidii not extending posterior of the 
columellar fossa (reversal, character 20), loss of enlarged preanal scales (character 14), 
variable number of phalanges (three or four) in pedal digit V (character 16). 

Although lacking a continuous venom groove (character 1) the late Cretaceous 
Paraderma bogerti is included within Helodermatidae because the jaws are suggestive 
of a varanoid having a stoutly constructed skull and rounded snout, and it has a dental 



195 



Table 5. Character distribution within Helodermatidae and outgroups, from Table 4(1= derived, = 
ancestral, 9 = missing data); a phylogeny is shown as Fig. 10. 



Character 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


11 


12 


13 


14 


15 


16 


17 


18 


19 


20 


Varanidae 















































0/1 


0/1 


0/1 


0/1 





Necrosauridae 











9 





























9 


9 





0/1 








9 


Paraderma 








1 


9 








9 


9 


9 


9 








9 


9 


9 


9 











9 


Eurheloderma 







1 











9 


1 


9 











9 


9 


9 


9 


9 








9 


Lowesaurus 







1 











1 


9 


9 











9 


9 


9 


9 


9 








9 


H. texanum 




1 








1 














1 





1 


9 


9 


9 


9 


9 








9 


H. suspectum 




1 


1 


1 


1 











1 


1 


1 


1 


1 





1 





1 


1 


1 





H. horridum 




1 


1 


1 


1 


1 








1 


1 


1 


1 





1 





1 











1 



morphology that can be interpreted as "early helodermatid." This implies that helo- 
dermatids diverged rather early from their varanoid ancestry in a split that primarily 
favored different predatory modes. In varanines and lanthanotines the skull is consid- 
erably narrower than its length, whereas that of helodermatids is nearly as wide as long. 
McDowell and Bogert (1954) considered the skull of Heloderma to be an early stage 
in a progressive modification of the "platynotan type." As viewed by us, it appears 
that the morphology of the helodermatid skull probably evolved in response to these 
squamates using massive, powerful jaws to kill and partially process large, defenseless 
prey. Varanids on the other hand differentiated as active, searching predators on rel- 
atively smaller prey. In this respect, Paraderma bogerti appears to be derived in the 
direction of helodermatids. 

By contrast, we can remove Gobiderma pulchrum from consideration as a helo- 
dermatid. This fossil was described by Borsuk-Bialynicka (1984) from a nearly complete 
skull and mandible (holotype ZPAL MgR-III/64) and two other partial skulls that were 
taken from ?middle Campanian Red beds of Khermeen Tsav, Mongolia. Gobiderma 
was featured as a "" Heloderma-\ike lizard" although its precise relationship was left 
unresolved, being designated as a medium-sized "platynotan" of about 5 cm skull 
length. It differs critically from "necrosaurids" and other varanoids in possessing a flat 
parietal, one in which the adductors attach to the ventral surface; in this respect it is 
like Heloderma. The osteoderms are small, plate-like and have a pitted surface, but 
they are fused only to the posterior aspect of the skull. In several other features, however, 
Gobiderma is generalized compared to Heloderma: the maxillary segment is tapered, 
there is no approach or contact of the pre- and postfrontals above the orbit, and it 
retains the upper temporal arch. Actually, the overall appearance of the skull recalls 
that of Xenosaurus. In appreciating the peculiarities of this taxon, Borsuk-Bialynicka 
(1984) offered that it might have been "an Asiatic substitute of the American group 
[rather] than a group ancestral to the Helodermatidae." The external nares are not at 
all retracted in the manner of varanoids, nor do the subolfactory processes of the frontal 
exhibit the characteristic downgrowth and ventromedial contact. The tooth row is nearly 
entirely antorbital, although the maxilla appears to participate in the suborbital fenestra, 
to judge from her figures, plates and descriptions (Borsuk-Bialynicka 1984). We also 
leave this taxon unassigned pending further study of "Platynota" and Necrosauridae. 

III. An Evolutionary Scenario for Helodermatidae 

The goal of this section is to offer a natural history perspective of helodermatids 
that is consistent with their fossil history, phylogeny, ecology, and behavior. We make 
no attempt to invoke a particular process (e.g., natural selection) for the origin of 
adaptive patterns {cf. Greene 1 986). Our remarks are based on the phylogenetic analysis 
presented above, information in the literature, examination of stomach contents, casual 
observations on captive individuals, and unpublished observations provided by others. 
We are interested in identifying concordant changes in natural history and morphology 
through evolutionary time. Therefore, the discussion proceeds from higher taxa to the 



196 

species of helodermatids themselves. Because the relationships of varanoids to other 
anguimorphs are controversial, we rely on general attributes of anguids and xenosaurids 
to postulate the polarities of ecological and behavioral characteristics. 

Natural History of Anguids and Xenosaurids 

Relative to other living squamates (Pough 1980), anguids range in size from rather 
small (e.g., SVL of 55-70 mm in Elgariaparva Knight and Scudday 1 985) to moderately 
large (more than 500 mm total length in Ophisaurus apodus and some Diploglossus). 
A few species are fossorial (e.g., Anniella), but most are terrestrial {E. coeruled) or 
arboreal (Abronia). A semiprehensile tail is probably primitive for anguids (Greene 
1986). Most anguids are probably insectivorous, but some are known occasionally to 
eat vertebrates, for example E. multicarinata (Cunningham 1956). The anguid tongue 
is modified for chemoreception (Schwenk 1984) and likely plays a prominent role in 
finding and/or recognizing food. Greene (in Burghardt 1978) demonstrated innate 
chemically mediated recognition of prey by naive Gerrhonotus liocephalus. For reviews 
of lizard feeding biology see Greene (1982), Pough (1973), Regal (1978), and Stamps 
(1977). 

The New World xenosaurids inhabit crevices in rocks and trees (Alvarez del Toro 
1982, King and Thompson 1968). In captivity they are secretive and active noctumally 
{personal observation). Presch (1981) reported an iguanid lizard (Sceloporus) in the 
stomach of a Xenosaurus grandis from Mexico, although several dozen other stomachs 
of this species from the same locality yielded only a variety of insects (Greene and 
McDiarmid, unpubl. data). The only Old World xenosaurid, Shinisaurus crocodilurus, 
lives along streams where it feeds on tadpoles, fish and aquatic invertebrates. It bites 
powerfully if restrained (J. B. Murphy, personal communication). 

A number of antipredator responses are so widespread among anguids and xeno- 
saurids (as well as varanoids; see below) that they are surely ancestral for Anguimorpha. 
These squamates characteristically are cryptic, being of drab dorsal color that is marked 
by some type of disruptive pattern (e.g., cross bars). When threatened they attempt to 
flee towards the nearest retreat; if seized, they struggle violently, defecate copiously, 
hiss, gape and bite fiercely. The tail is autotomic in anguids (aside from Ophisaurus 
apodus) and Shinisaurus, but not in Xenosaurus {see Greene, MSa, for a review of 
defense behavior in lizards). 

Natural History of Varanus and Lanthanotus 

Varanids are small to very large lizards ( Varanus brevicauda, total length 24 cm 
vs. V. komodoensis, total length 3 m). The extinct Megalania prisca from the Quaternary 
of Australia is thought to have achieved a total length of 6 m (Hecht 1975). Judging 
from stomach contents of living species, an ancestral varanid was moderately large, 
terrestrial or semiarboreal, and fed on a variety of small invertebrates and vertebrates. 
Gigantism and consumption of relatively large vertebrates (mammals in the case of 
varanids) are probably derived attributes within Varanidae, as is extremely small size 
(Losos and Greene MS). Varanids have tongues that are highly modified for chemo- 
reception (Schwenk 1984) and apparently are used to locate hidden prey during their 
wide search activities (Auflenberg 1981, Pianka 1982, Losos and Greene MS). Varanids 
are cryptic, wary, and fast moving lizards that exhibit stereotyped threat postures when 
cornered. If approached or handled they lash with the tail, gape, hiss, struggle, defecate, 
and bite (Greene MSa). 

Almost nothing is known about the natural history of Lanthanotus borneensis. 
Apparently it is a specialized burrower, but swims well and has a partially prehensile 
tail (Proud 1978, Sprackland 1972). A specimen in the Museum of Comparative Zo- 
ology had earthworm setae in its gut (Greene, unpublished data). Captives flatten their 
body when threatened, and when handled struggle, defecate, hiss, and sometimes bite 
(Greene MS<2). 



197 

Natural History of Living Helodermatids 

Behaviorally and morphologically helodermatids are in some respects generalized 
varanoids. Like other anguimorphs and unlike varanids, the two living helodermatids 
prefer relatively cool temperatures (John-Alder et al. 1983). They arc not as agile as 
varanids, yet not so clumsy as often portrayed. The popular vision of a rotund, sluggish 
beast stems from the appearance of captive specimens (usually Helodenna suspect urn) 
that have been housed in small cages and fed a diet of infertile chicken eggs. It is true 
that Gila monsters (//. suspectum), being shorter and stouter, resemble this portrait 
more so than do Beaded lizards (//. horhdum). Our observations on both species are 
consistent with those of John-Alder et al. (1983), that these animals cannot capture an 
adult, uninjured rodent except in a very confined space. Nevertheless, helodermatids 
typically take a broader range of prey than is implied by the usual captive diet. Freshly 
collected individuals, especially H. horhdum, are rarely, if ever, obese. 

Bogert and Martin del Campo (1956) summarized records for natural prey of 
Helodenna horhdum, based on stomach and/or intestinal contents of 20 animals. These 
consisted of five mammals, including a rabbit (Sylvilagus sp.) and a cotton rat {Sig- 
modon sp.) found in one stomach; two birds including a nestling squirrel cuckoo {Piaya 
cayana); ten sets of bird eggs, numbering up to 13 per stomach and possibly including 
those of unidentified doves and Douglas quail (Lophortyx douglasi); two sets of reptile 
eggs, numbering up to 35 per stomach, including those of an unidentified lizard and 
of a turtle (Kinosternon); and six sets of insect parts that the authors discounted as 
likely to have been ingested accidentally. Bogert and Martin del Campo (1956) also 
noted that some H. horridum they examined were juveniles, suggesting, perhaps, that 
there are no major ontogenetic changes in diet. In the KU and Los Angeles County 
Museum collections we examined the stomachs of five beaded lizards that contained 
prey, the food items consisting of two sets of reptile eggs, a set of bird eggs, and two 
sets of large coleopteran larvae (includes items mentioned by McDiarmid 1963). 

Bogert and Martin del Campo (1956) also summarized published observations on 
the natural prey of 1 1 Heloderma suspectum. They found 14 mammals (ground squirrels 
and rabbits) in nine animals, reptile eggs in four, bird eggs in one, and a lizard in one. 
Using radiotelemetry, Jones (1983) studied the foraging biology of nine H. suspectum 
in Arizona. The individuals he followed hunted over wide areas, and consumed 24 sets 
of quail eggs, two sets of dove eggs, and three mammals, or groups of mammals. 

The climbing habits of helodermatids have been known for some time (Bogert and 
Martin del Campo 1956), but only recently has there been substantial evidence to 
document this activity. Cross and Rand (1979) observed two Heloderma suspectum 
for more than 1 5 hours, and witnessed each animal ascend and descend the rough bark 
of a desert willow; in one case the tail was used in locomotion. Alvarez del Toro ( 1 982) 
described climbing behavior and semiprehensile use of the tail by captive H. horridum 
collected from Chiapas, Mexico. J. W. Hardy {personal communication) found adult 
H. horridum raiding the nests of Beechey's jay {Cissilopha beecheyi), high in trees in 
Nayarit, Mexico. 

Greene raised a juvenile Heloderma horridum (initial weight ca. 55 grams) from 
Colima, and observed frequent arboreal activity. The lizard was kept in a 20 gal 
aquarium containing a hollow limb that extended from one bottom corner diagonally 
up to the opposite comer. The beaded lizard spent most of its time concealed in a 
cavity at the upper extent of the limb, emerging only to feed and drink. It climbed 
without difficulty, and curled its tail about branches when descending. Ambulatory 
juvenile mice were chased and subdued without obvious difficulty, albeit somewhat 
clumsily. 

Helodermatids spend large amounts of time in underground burrows (Bogert and 
Martin del Campo 1956, Cross and Rand 1979, Jones 1983); they are potentially more 
vulnerable to predators when hunting. If threatened, individuals of both species 
usually flee towards shelter in a bush or burrow. An adult Heloderma horridum in 
Oaxaca, Mexico, rapidly ascended a pine tree when it was approached (V. Fitch, personal 



198 



cummunication). If a helodermatid is aggravated or handled, it hisses, gapes, struggles, 
and bites (Bogert and Martin del Campo 1956). 

Adaptive Trends among Varanoidea 

Anguimorphs probably began as terrestrial and semiarboreal squamates in tropical 
or subtropical mid-latitudes of Laurasia during the late Mesozoic {see above and Estes 
1983Z)). They fed predominantly on insects that were encountered by searching actively, 
using both visual and chemical cues. Larger species preyed on large insects and the 
occasional small vertebrate. Primitively, varanoids were larger than other anguimorphs, 
and more widely foraging. Likely, they relied more on chemoreception for locating prey 
and took vertebrates more often, but these were probably small relative to their body 
size. The defensive behavior of helodermatids and Lanthanotus is similar to that of 
anguids and xenosaurids, and except for venom use in helodermatids, is likely to 
represent an ancestral anguimorph response. 

The adaptive zone of monitor lizards ( Varanus) is specialized beyond the primitive 
varanoid condition. Physiologically these animals are capable of unusual locomotor 
stamina (Bennett (1978), they prefer high temperatures, and travel extensively while 
hunting (Auffenberg 1981, Losos and Greene MS, Pianka 1982). Predation on large 
mammalian prey (e.g., by Varanus komodoensis, Auffenberg 1981) is a derived con- 
dition within Varanidae, and involves ingestion of pieces rather than large, intact items. 
The living members of the subfamily exhibit considerable ecological diversity (Auf- 
fenberg 1981, Greene 1986) although most species are reasonably similar in their feeding 
biology (Losos and Greene MS). 

What little is known about Lanthanotus borneensis suggests that this bizarre crea- 
ture is a burrower. For instance certain cranial features shared with other anguimorphs 
are associated with fossoriality (Borsuk-Bialynicka 1984, Gauthier 1982, Rieppel 1983). 
If some or all of the synapomorphies of Lanthanotinae are functionally related to 
fossoriality, they represent an adaptive shift that is unique in the evolution of varanoids. 

Available information shows that living helodermatids take a potential range of 
prey types, from vertebrate eggs to large insect larvae, and that mammals are of major 
importance. Although complete comparative data are lacking, it appears that both 
species may take relatively larger, intact prey than any other living squamate aside 
from some snakes (Stahnke 1952, Greene 1982, 1983). Hunting is characterized by 
wide searches and investigating specific sites in terrestrial and arboreal microhabitats 
{see above and Bogert and Martin del Campo 1956, Jones 1983). 

There is evidence that tissue-destructive venoms of viperid snakes facilitate diges- 
tion of large, bulky prey, especially under conditions like mild temperature where such 
items might putrify prior to digestion by intestinal secretions (Greene 1983, MSb, 
Pough and Groves 1983, Thomas and Pough 1979). Venom injection is a derived 
characteristic of Helodermatidae, developed most fully in Heloderma, and we suggest 
that it is an adaptation for preying on large, bulky vertebrates under temperature regimes 
that are periodically cool. Information on the venom of helodermatids is incomplete, 
sometimes contradictory (Russell and Bogert 1981), and controlled studies using natural 
prey would be of great interest. 

Evolutionary trends in diet parallel morphologies of the tongue and throat region 
of Varanoidea (McDowell 1972, Schwenk 1984). Anguimorphas primitively have a 
tongue that is functionally and structurally divided, such that the hind-tongue functions 
in food transport and the foretongue serves as a chemoreceptor (via taste buds, Schwenk 
1984) and a vehicle for carrying odor molecules to the vomeronasal organ. McDowell 
(1972) noted that helodermatids show features plausibly related to increased gape (e.g., 
reduction of the posterior limbs of the tongue), and suggested that the tongue of Lan- 
thanotus is used to swallow "less bulky food" than that of helodermatids. The tongue 
of Varanus is highly derived and protrusible; it serves a chemoreceptive role and no 
longer functions in frictional food transport. Swallowing in monitors results entirely 



199 



from throat compression, lateral movements of the neck, and esophageal peristalsis 
(Smith 1986). 

Bogert and Martin del Campo (1956) commented that in helodermatids venom 
was certainly not necessary to immobilize prey and, because it is clearly associated 
with the bite, they hypothesized that venom and teeth are primarily a means for 
thwarting predation. That explanation is consistent with other research demonstrating 
that wide foraging habits and preoccupied feeding techniques (e.g., digging for prey) 
often correspond with increased risk of predation (Huey and Pianka 1981, Vitt 1983), 
and the evolution of defensive specializations (Greene MSa). We favor the hypothesis 
that venom delivery in helodermatids evolved in a feeding context and was later co- 
opted for defense under some circumstances {see below). However, a decisive choice 
between these alternatives is as yet not possible. 

The two living species of Heloderma differ mainly in three characteristics. Helo- 
derma horridum has a higher mean number of subdigital scales and a longer tail. An 
increased number of subdigital lamellae is associated with arboreality in certain other 
lizards {Anolis, Collette 1961; Aristelliger, Hecht 1952). However, high lamellar counts 
and arboreality are also correlated with increased body size in those taxa and in H. 
horridum, thus obscuring functional interpretations and character state polarities. To 
judge from other anguimorphs, including varanids (Mertens 1942, Greene 1986), the 
high subdigital scale counts and the comparatively long, semiprehensile tail of H. 
horridum are primitive for varanids, and probably anguimorphs. They need not be 
explained as specializations arising in Heloderma. The short tail and toes of H. sus- 
pectum are derived attributes, perhaps associated with fat storage and digging for prey, 
respectively. 

Heloderma horridum is a predominantly black animal with irregular yellow mark- 
ings on the body and yellow rings on the tail [adult H. h. alvarezi are entirely black, 
whereas juveniles are patterned like adults of other subspecies (Alvarez del Toro 1 982)]; 
H. suspectum is a black and pink animal, the latter color often predominating. A 
mottled, cryptic dorsal pattern and a ringed tail, as in H. horridum, are probably 
ancestral for anguimorphs (Gauthier 1 982, Greene 1 986). The more brightly contrasting 
pattern of H. suspectum is clearly derived; it is probably both cryptic and aposematic 
(Bogert and Martin del Campo 1956), and functionally coupled with the venomous 
bite. 

The moderate diversity and fairly widespread occurence of helodermatids in North 
America and Europe during the late Cretaceous and early and middle Tertiary suggest 
that they inhabited a once broader spectrum of environments than would be inferred 
from their present distribution. Our analysis indicates that primitively these venomous 
varanoids inhabited non-desert environments, and that among the two living species 
the habits and habitat of Heloderma horridum are more representative of an ancestral 
helodermatid. The few derived attributes of//, suspectum are associated with the xeric, 
open conditions characteristic of the latest Cenozoic in southwestern North America. 

Although they resemble ancestral varanoids in several respects, helodermatids 
exhibit morphological and natural history traits that are derived and unique among all 
other living squamates. Our appraisal of their known history and biology suggests that 
the extant species are appropriately regarded as living fossils. 



Acknowledgments 

Throughout the protracted development of this study we have approached innu- 
merable colleagues for loans of specimens, access to their notes and ideas, and comments 
on the manuscript. Each responded generously and it is our regrettable oversight if we 
fail to mention some of them by name. 

For loaning fossil material we are grateful to D. Baird, H. Hutchinson, G. Gaffney, 
P. Gingerich, W. Langston, L. D. Martin, and M. Voorhies, and for comparative 



200 



skeletons B. Brattstrom, R. Drewes, W. E. Duellman, R. Etheridge, M. Greenwald, R. 
Heyer, A. Kluge, A. Leviton, C. Myers, W. Presch, G. Zug and R. Zweifel. 

Opportunities to study live anguids, helodermatids, xenosaurids, a Lanthanotus, 
and varanines were provided by J. A. Campbell, K. Klemmer, R. W. McDiarmid, J. 
B. Murphy, W. E. Rainey, L. J. Vitt, and T. B. Johnson and C. Schwalbe of the Non- 
game Branch of the Arizona Game and Fish Department. 

For providing access to computer facilities and consultation we thank A. Kluge 
and W. Presch. 

We especially appreciate the kindness of Richard Estes for his ideas, discussion, 
and comments on the manuscript, various drafts of which were also read by D. R. 
Frost, K. de Queiroz, D. Good, M. Lang, J. B. Losos, W. Presch, and R. W. McDiarmid. 

Figures 3 and 10 were drawn by Lynn A. Barretti. 

Greene's studies were supported by the National Science Foundation (BNS 76- 
19903, BSR 83-00346) and the Museum of Vertebrate Zoology (Annie M. Alexander 
Fund). Gauthier received support from the Theodore Roosevelt Memorial Fund 
(AMNH), the California Academy of Sciences, and NSF grant BSR-8304581. Pregill's 
work was aided in part by the Smithsonian Institution during a Postdoctoral Fellowship 
at the United States National Museum, and from NSF grant DEB-8207347. 



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p.yiQ7 TRANSACTIONS 

LIPRARY OF THE SAN DIEGO 

SOCIETY OF 
MAR 71388 NATURAL HISTORY 

HARVARD 
UNIVERSITY 

Volume 21 Number 12 pp. 203-220 24 February 1988 

Camaenid land snails (Gastropoda: Pulmonata) from the Eocene 
of southern California and their bearing on the history 
of the American Camaenidae 

Barry Roth 

Museum of Paleontology, University of California, Berkeley, California 94720 USA 

Abstract. Zachrysia fraterna. new species, is described from the upper middle Eocene Friars 
Formation. San Diego County, California. All other records of Zachrysia are from Cuba, as Quaternary 
fossils or living. The presence of Z. fraterna implies forested land and a tropical climate with ample 
summer rainfall. Two Eocene species, described as Helminthoglypta obtusa from the Tejon Formation 
and HP. stocki from the Sespe Formation, are not Helminthoglyptidae but Camaenidae. Discoveries 
of extant Neotropical camaenid genera as Paleogene fossils in North America establish a middle Eocene 
minimum age for these genera and constrain hypotheses about the sources and timing of origin of the 
Caribbean biota. Recent and fossil distributions form a north-south generalized track from North 
America to the Caribbean region. As a family the Camaenidae show the "interrupted Tethyan" type 
of distribution. Links between the American and Australasian groups of Camaenidae are more likely 
to be found in Europe and western Asia than in the Pacific realm. 

Introduction 

The Camaenidae are a large family of pulmonate land snails with a discontinuous 
distribution. One branch of the family inhabits the West Indies, Central America as 
far north as Costa Rica, and Andean South America as far south as Peru. The other 
branch extends from eastern India and southern China through the Solomon Islands, 
south into the northern three-quarters of Australia, with a few taxa extending as far 
north as southern Japan (Solem 1979). Several recent studies have documented the 
presence of camaenid land snails in lower Tertiary strata of western and mid-continent 
North America (Solem 1978, 1979; Bishop 1979; Roth 1984). 

In 1985 members of the Department of Paleontology of the San Diego Natural 
History Museum collected fossil invertebrates from a marine stringer in the predom- 
inantly nonmarine Friars Formation, of Eocene age, in southwestern San Diego County, 
California. Three taxa of nonmarine gastropods were present, including a well-preserved 
specimen that is conchologically indistinguishable from the modern camaenid genus 
Zachrysia Pilsbry, 1 894. Zachrysia is otherwise known only from Cuba, as living species 
or Quarternary fossils. In addition, the type material of two southern Californian Eocene 
species originally assigned to Helminthoglypta Ancey, 1887, has been reviewed. With 
different degrees of certainty, those species are also assignable to Camaenidae. 

The sources of the fossils discussed in this paper are shown in Figure 1 . Figure 2 
presents the correlation of rock units yielding camaenid fossils in western North Amer- 
ica; age and geologic setting are discussed further below. 

There is now enough material available to show that as early as middle to late 
Eocene time the American Camaenidae were differentiated into several genera of mod- 
ern aspect and arrayed across at least the southern part of North America, perhaps 
roughly paralleling the remnants of the Tethyan seaway. The biogeographic history of 
the group since that time has consisted largely of a southward, and to some extent east- 
west, restriction to the present Caribbean region along with the development of a 
distinctive pattern of insular allopatry. 



204 



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Tejon Formation, Live Oak Creek; 2, Sespe Formation, Tapo Canyon; 3, Mission Valley and Friars for- 
mations, San Diego area. 

Fortunately for paleontologists, the shells of American Camaenidae are usually 
diagnostic at the generic, and sometimes the subgeneric, level. The definitive anatomical 
work on the group (Wurtz 1955) did little to alter the earlier concepts of genera founded 
on conchological characters. With a few modifications after Solem (1966), Wurtz's 
anatomical study formed the basis for the phylogenetic analysis proposed by Bishop 
(1979) and accepted here without changes. 





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Figure 2. Correlation of Eocene and Oligocene formations in California, Texas, and Nebraska that have 
yielded camaenid land snails. Solid triangles indicate approximate stratigraphic positions of camaenid fossils. 



205 

The following abbreviations are used: CAS, Department of Geology, California 
Academy of Sciences; CIT, California Institute of Technology (collections now at 
Natural History Museum of Los Angeles County); LACMIP, Section of Invertebrate 
Paleontology, Natural History Museum of Los Angeles County; SDSNH, Department 
of Paleontology, San Diego Natural History Museum; UCMP, Museum of Paleontol- 
ogy, University of California, Berkeley. 

Systematic Paleontology 

Class Gastropoda Cuvier, 1797 

Subclass Pulmonata Cuvier, 1817 

Order Sigmurethra Pilsbry, 1900 

Superfamily Camaenacea Pilsbry, 1895 

Family Camaenidae Pilsbry, 1895 

Zachrysia Pilsbry, 1894 

Zachrysia Pilsbry 1894:97. Pilsbry 1929:581-606. Wurtz 1955:135-137. Zilch 1960:598. 

Tvpe species. —Helix auricoma Ferussac, 1 82 1 , by subsequent designation (Pilsbry 
1929:586). Recent, Cuba. 

Generic diagnosis. —S\\q\\ white with brownish-yellow periostracum, depressed glo- 
bose, with small spire and few, rapidly expanding whorls; the first 1.5 embryonic, 
polished, the first half whorl with extremely fine microscopic spiral lines, the next with 
fine axial riblets, the rest with oblique growth striae and extremely fine, dense granules, 
mostly arranged in irregular spiral lines. Last whorl rounded, somewhat flattened below, 
not umbilicate. Aperture very oblique, without teeth; peristome expanded; basal margin 
elongated, turned up and appressed (Zilch 1960, translation). 

In some species all embryonic sculpture may be nearly obsolete (Pilsbry 1929). 
The genital system includes distinctive characters which are of course inaccessible on 
fossil specimens. 

The several subgenera of Zachrysia are founded on characteristics of the genital 
system (Pilsbry 1929, Bonilla 1936, Wurtz 1955). Minutely decussate shell sculpture 
occurs only in the subgenus Megachrysia Pilsbry, 1929, but otherwise there are no 
conchological characters that discriminate the subgenera. The following fossil species 
is therefore assignable to the genus in the broad sense only. 

The modem range of Zachrysia is limited to Cuba, with several human introduc- 
tions elsewhere in the Caribbean region. The only other fossil record is "along the shore 
east of Punta San Juan de los Perros," Cuba (Pilsbry 1929:603), where specimens of 
Z. auricoma occur in a presumably Pleistocene or Holocene deposit. 

Zachrysia fraterna, new species 
Figures 3, 4 

Holotype. -SDSNH 28388. 

Tvpe locality. —SDSNH Loc. 3278, San Diego County, California. Construction 
site at' 4760 Murphy Canyon Road, San Diego (39°49'26"N; 1 17°07'05"W), exposing 
1 5 m of Friars Formation and at least 8 m of overlying Stadium Conglomerate, elevation 
71 m; collected by B. O. Riney, 23 February 1985. Friars Formation, upper middle 
Eocene. From blue-gray conglomeratic sandstones at the base of a 50-70 cm-thick 
graded bed, approximately 12 m below the Friars Formation-Stadium Conglomerate 
contact. A retaining wall now covers the collecting site. 

Diagnosis.— A small, depressed-helicoid Zachrysia with 4.8 whorls, attenuated 
base, smooth, sinuous radial riblets, and reflected but not greatly thickened lip. 

Etymology.— The species is named for the Friars Formation {fraterna, L., broth- 
erly). 

Description.— SheW small for the genus, thin, inflated, depressed-helicoid, imper- 
forate, broadest above middle of body whorl; base attenuated. Spire low, weakly convex 
in profile; suture moderately impressed. Embryonic whorls 1 .4, smooth. Early teleo- 



206 














Figures 3-12. 3, 4, Zachrysia fratema, n. sp., holotype, SDSNH 28388, top and apertural views; major 
diameter 23.5 mm. 5, 6, Zachrysia auricoma havanensis (Pilsbry), Holocene, Havana, Cuba, top and apertural 
views; major diameter 25.7 mm (author's collection). 7-10, Lahyrinthus obtusus (Anderson and Hanna), 
holotype, CAS Geology Type Collection 1016, top, apertural, lateral, and basal views; diameter 16.0 mm; 
arrowhead points to basal constriction. 1 1, Labyhnthusp.) sp., SDSNH 32044, top view; diameter 12.6 mm. 
12, Labyrinthus manueli Higgins, Holocene, Mera, Ecuador, lateral view; diameter 21.7 mm (CAS). 



conch whorls irregularly corrugated by low growth rugae which grade, from about 
beginning of fourth whorl on, into acute, raised, more or less regularly spaced, sinuous 
radial riblets. Riblets convex in direction of growth on shoulder of whorl, retractive at 
periphery, shallowly concave below periphery, and almost straight where they cross 
the base; riblets on body whorl subequal in strength and spacing, triangular in cross- 
section, smooth, or obscurely beaded by faint wrinkling below suture. Periphery of 
penultimate whorl rounded-subangular, grading to broadly rounded on body whorl. 
Last Vs whorl descending steeply to aperture, apico-basally compressed, constricted 
behind lip. Aperture broadly ovate, markedly oblique, at angle of 60° to vertical; lip 
expanded and strongly reflected, curving backward over pre-apertural constriction. 
Parietal wall calloused, striate, reflecting underlying riblets. Basal lip rather wide, com- 
pressed upward, thickened, columellar portion (all preserved) with a shallow sulcus 
running outward from umbilical region. Major diameter (incomplete) 23.5 mm, minor 
diameter 19.3 mm, height 16.9 mm; whorls 4.8. 

Discussion.— Zachrysia fratema differs from all other species of the genus in having 
4.8 whorls. As described by Pilsbry (1929), modem Cuban species have from 4 to 4.5 



207 

whorls. However, the low-helicoid shape, rapidly expanding whorls, and attenuated 
base rapidly sloping from the periphery to the columellar area leave no doubt that this 
is a species of Zac/irysia. The sinuous radial sculpture is also typical of the genus. The 
lower edge of the aperture of the holotype is broken, but the remaining columellar 
portion shows that the basal lip was thickened and compressed upward as in modern 
species and may have had a shallow sulcus running along its length. There is no 
indication whether or not denticles were developed on the basal lip. 

The holotype has been slightly compressed in a direction normal to the plane of 
the aperture, accentuating the difference between major and minor diameters. 

The shell structure consists of (1) an outer, radial crossed-lamellar layer with first- 
order lamellae parallel to the direction of growth; (2) a middle, concentric crossed- 
lamellar layer with first-order lamellae at right angles to the first; and (3) an inner, 
concentric crossed-lamellar layer (terminology after MacClintock 1967). The contact 
between the outer and middle layers is gradational, with the first-order lamellae 
undergoing a 90° rotation in the plane of the shell surface. The contact between the 
middle and inner layers is sharp and unconformable, with a tendency for the two layers 
to separate at the site of a break. The outer layer makes up about 20% of the total 
thickness of the shell. The middle and inner layers each make up about 40%, but the 
thickness of the inner layer is variable. Thickening around the peristome results mainly 
from augmentation by the inner layer. Modern Zachrysia auricoma shows the same 
sequence and relative thickness of shell layers, supporting the generic assignment. 

No single modern taxon stands out as conchologically most similar to Z. fraterna, 
but Zachrysia auricoma, particularly the small-shelled subspecies Z. a. havanensis 
(Pilsbry, 1894), is generally similar in size and outline (Figures 5, 6). The periphery of 
the penultimate whorl of Z. fraterna is less broadly rounded and is almost angulate 
where the last whorl begins its descent to the aperture. The angulation is not as acute 
as in Zachrysia torrei (Henderson, 1916) (Pilsbry 1929:pl. 29, figs. 8, 10). 

Based on the scanty data of this one Eocene specimen and the twenty or so extant 
species, one can infer that the trend of shell evolution in Zachrysia has been toward 
(1) larger overall size, (2) reduced number of whorls, and (3) more rapidly expanding 
whorls, producing a larger shell at a given whorl number. At the same time, the overall 
shape has held remarkably constant. 

Associated fauna. —The holotype (and only specimen) was found in a marine sand- 
stone stringer in the mainly nonmarine Friars Formation, associated with a moderately 
diverse nearshore molluscan assemblage dominated by Pachydesma sp.. cf. P. kellogg- 
ensis (Clark and Woodford, 1927), Tellina soledadensis Hanna, 1927, and Turritella 
uvasana Conrad, 1855, sensu lato. Rare estuarine molluscan taxa, including Loxotrema 
turritum Gabb, 1868, and Merita triangulata Gabb, 1869, were also present (T. A. 
Demere, personal communication 1986). Two other taxa of nonmarine mollusks were 
present: (1) an almost planispiral gastropod 6.3 mm in diameter and 2.3 mm high, 
consisting of 3.4 whorls, somewhat suggesting the ammonitellid genus Megomphix 
Baker, 1930, but not further identifiable because the surface sculpture is not preserved; 
and (2) two partial spires of lenticular pulmonate land snails, 12.9 and 13.6 mm in 
maximum preserved diameter, of 4.7 and 4.2 whorls respectively, with ver\' oblique 
growth striae and subangular periphery. These are discussed under LabyrinthusO species, 
below. 



Labyrinthus Beck, 1837 

Labvrinthus Beck 1837:33. Wurtz 1955: 114-11 7 (in part). Zilch 1960:602-603 (in part). Solem 

' 1966:37^4. 
Ambages Gndt 1912:21-23. Wurlz 1955:114. 

Type species. — Helix labyrinthus "Chemnitz" Deshayes, 1838 {=Helix otis Light- 
foot, 1786), by subsequent designation (Herrmannsen 1846:569). Recent, Costa Rica 
to Colombia. 



208 



Generic diagnosis. — Shell small to large; depressed globose to planulate; surface 
sculpture of growth wrinkles or granulations, but never ribbed; spire nearly flat to 
moderately elevated; periphery rarely rounded, usually acutely angulated or protrud- 
ingly keeled; umbilicus partly (rarely completely) closed by extension of basal and 
parietal lips; aperture strongly deflected near end of body whorl, partially obstructed 
in adult by gross expansion of lips and development of various denticles and lamellae; 
parietal lip raised and with reflected edge, basal and palatal lips thickened and strongly 
reflected; parietal wall with single short to long, curved to sinuated lamella that stops 
short of or merges with the elevated parietal lip; basal lip straight to sinuated, normally 
with one lamellar knob marking its outer boundary, occasionally with a second inner 
knob; lower palatal lip with single crescentic lamella, hooked lamellar tooth, large 
transverse lamellar plate or y-shaped bifid tooth with deep indentation behind lip; 
upper palatal lip with weak lamella or triangular knob in a few species (Solem 1966). 

Solem's (1966) monograph gave generic rank to Isomeria Albers, 1850, which both 
Wurtz (1955) and Zilch (1960) had treated as a subgenus of Labyrinthus. While noting 
that anatomical evidence did not support separation of Labyrinthus and Isomeria, 
Solem gave them coordinate rank because of shell characters and altitude ranges. 

Although it is not stated explicitly. Bishop's (1979) figures 20-21 show that he 
used "'Labyrinthus'' in the inclusive sense of Wurtz (1955) and Zilch (1960). 

In spite of these differing opinions as to taxonomic rank, all authors agree that 
Labyrinthus plus Isomeria form a monophyletic group distinct from the rest of the 
American Camaenidae. It is to be expected that fossil species may be found that cannot 
be assigned to one or the other but only to a Labyrinthus-Isomeria lineage. Note that 
two Holocene species, Isomeria minuta Solem, 1966, and /. inexpectata Solem, 1966, 
are regarded as intermediate in shell characters (Solem 1966:127-128). 

The modern range of Labyrinthus extends from northern Costa Rica south to 
Madre de Dios, Peru, east to Caracas, Venezuela, and Para, Brazil (Solem 1966). No 
other fossil occurrences are known, although "Camaenid, genus and species indet." of 
Roth (1984:210-21 1, figs. 29-31) shows some similarity to Labyrinthus and Isomeria. 

Labyrinthus obtusus (Anderson and Hanna, 1925) 

Figures 7-10 

Helfninthoglvpta obtusa AndQvsomindY\a.nndi 1925: 142-143, pi. 3, figs. 12, 13. Henderson 1935: 
141. Piisbry 1939:66. 

Holotype.— CAS Geology Type Collection 1016. 

Type locality. —Kern County, California. Live Oak Creek. Collected by M. A. 
Hanna, 1922. Tejon Formation, Eocene. 

Description.— The holotype is an internal mold with original shell material ad- 
hering; the shape is roughly lenticular, flatter above and more deeply convex below the 
periphery. The external surface appears to be well preserved. The protoconch and spire 
are smooth and unsculptured. The body whorl is sculptured with traces of oblique 
growth striae. There are 4.75 whorls preserved, but there were probably about five 
originally. The whorls are closely coiled, not rapidly expanding; the slight elliptical 
eccentricity visible in top view is probably the result of post-mortem compression. The 
whorl cross-section is lunate; the parietal wall is missing. The base is narrowly um- 
bilicate, the umbilical region filled with matrix that shows the impression of an ex- 
panded, reflected columellar lip (now missing) that must have covered or nearly covered 
the umbilicus. The suture is well marked and there is no trace of reabsorption of internal 
whorl partitions; i.e., L. obtusus is a pulmonate, not a prosobranch. Only the basal part 
of the peristome is preserved but that is thickened and reflected. Just in back of the 
peristome the base of the body whorl is strongly constricted upward. 

Diameter of holotype (incomplete) 16.0 mm, height 9.6 mm. 

Discussion.— The distinct upward constriction of the base of the body whorl im- 
mediately behind the aperture, the thickened and reflected peristome, and the lenticular 
profile, more deeply convex below the angulate periphery, all indicate assignment to 



209 



Labyrinthus. A specimen of Lahyrinlhus manueli Higgins, 1872, is illuslraled for com- 
parison (Figure 12); the similarities are most apparent in lateral view. 

Anderson and Hanna (1925) construed Helminthoglypta rather broadly and in- 
cluded species that would now be allocated to Monadenia Pilsbry, 1890. The shells of 
most Monadenia species are pustulose or finely spirally striate; they have distinctive 
protoconch sculpture of granules or clothlike texturing (Roth 1981). None has a basal 
constriction behind the aperture. 

Helminthoglypta includes species with shells of moderate to large size, helicoid or 
depressed, with conic or low spire, open or covered umbilicus, and periphery rounded 
to angular in the subadult (Pilsbry 1939). A wide range of shell forms is found, from 
globose-conic and higher than broad to nearly planispiral. In all, however, the peristome 
is reflected simply, without being preceded by a basal constriction. 

Several Holocene species of Labyrinthus become adult in the 15-20 mm diameter 
size range, although most are larger (to 60 mm). In all modern species the basal con- 
striction is pronounced and the aperture furnished with various denticles and lamellae. 
Because the aperture of the holotype of L. obtusus is incomplete and the parietal wall 
is missing, no more detailed comparison with the modern species groups of Labyrinthus 
is possible. 

Labyrinthus{7) species 
Figure 1 1 

Referred material and locality.— T-wo specimens, SDSNH 32044; from SDSNH 
Loc. 3278, San Diego County, California. Construction site at 4760 Murphy Canyon 
Road, San Diego (39°49'26"N; 1 17°07'05"W), exposing 15 m of Friars Formation and 
at least 8 m of overlying Stadium Conglomerate; elevation 7 1 m; collected by B. O. 
Riney, 23 February 1985. Friars Formation, upper middle Eocene. From blue-gray 
conglomeratic sandstones at the base of a 50-70 cm-thick graded bed, approximately 
12 m below the Friars Formation-Stadium Conglomerate contact. 

Description. —The material consists of two partial spires (with some internal whorls 
present) of lenticular land snails, 12.9 and 13.6 mm in maximum preserved diameter, 
consisting of 4.7 and 4.2 whorls respectively. The specimens are immature, without 
thickened lip, constricted body whorl, or other characters of terminal growth. The shell 
is more deeply convex below the subangular periphery. The whorls are closely coiled, 
not rapidly expanding; the whorl cross-section was apparently lunate. The base and 
umbilical region are not preserved. The suture is well marked and there is no indication 
of reabsorption of internal whorl partitions; i.e., they are pulmonates, not prosobranchs. 
The protoconch apparently consists of 1.5-1.7 whorls but is not well diflerentiated 
from the neanic whorls. The only sculpture consists of low, oblique growth rugae. Both 
specimens are slightly elliptical in top view, probably due to post-mortem distortion. 

Z)/5a/55/OA7.— Without specimens showing the thickened and reflected lip of ma- 
turity, it is not possible to allocate this material more securely. However, the characters 
preserved— tight coiling, the general absence of sculpture other than growth rugae, the 
low spire, and greater convexity below the subangular periphery— are consistent with 
Labyrinthus and similar to L. obtusus from Kern County. The two specimens are smaller 
at a given whorl than the holotype of L. obtusus; the protoconchs are slightly smaller, 
and the growth rugae stronger. 

Genus uncertain 

[Camaenidae] 5rc»cA:/ (Hanna 1934) 

Figures 13-17 

Helminthoglypta'? stocki Hanna 1934:539, texi-figs. l-3a. Pilsbry 1939:66. 

Type material and locality. — Hololypc: LACMIP 4261 (formerly CIT 3244). from 
CIT vertebrate paleontology locality 180, Ventura County, California. Tapo Canyon, 
north of Simi Valley. Sespe Formation, lower upper Eocene. Two paratypes, LACMIP 



210 




Figures 13-17. [Camaenidae] stocki (Hanna). 13-15, holotype, LACMIP 4261, top, basal, and apertural 
views; diameter 38.0 mm. 16, 17, paratype, LACMIP 4262, detail of sculpture on body whorl and basal 
view; diameter 44.0 mm. 



4262 and 4263 (formerly CIT 3246 and 3245, respectively), from same locality as 
holotype. 

Referred material and locality.— UCMF loc. D-781 1, San Diego County, Califor- 
nia. At intersection of Lake Murray Blvd. and Dallas Street behind the Jack-in-the- 
Box drive-in (WV2 SE'/i sec. 7, T. 16 S, R. 1 W, San Bernardino Base and Meridian); 
elev. 190 m [625 ft]. Mission Valley Formation, upper middle Eocene. This is the same 
as UCMP vertebrate locality V-6893, the Jack-in-the-Box locality of Golz and Lille- 
graven (1977) and other vertebrate workers. 

Description. —The holotype and two paratypes are internal molds with thin partial 
crusts of recrystallized shell material, and a matrix of reddish and greenish lithic wacke. 
Patches of external sculpture are preserved on the last whorl of the holotype and paratype 
LACMIP 4262; they consist of fine, raised, axial riblets oblique to the direction of 
spiral growth, apparently parallel to lines of growth (Figure 1 6). The riblets do not 
anastomose, and each evidently retains its distinctness across the whorl. The apices of 
the shells are not well preserved. Hanna (1934) estimated about 6.5-7 whorls, but I 
judge only about five to be present. The whorls are closely coiled and do not expand 
rapidly. The whorl cross-section was apparently higher than broad, and ovate to sub- 



211 



Table 1 . Measurements of type specimens of [Camaenidae] stocki (Hanna 


1934). 




Holotype LACMIP 

4261 


Paratype LACMIP 

4262 




Paratvpe LACMIP 
4263 


Diameter: 38.0 mm 
Height: 36.2 


44.0 mm 
29.9 (skewed) 




36.7 mm 
26.0 



lunate. The base is umbilicate, best shown by paratype LACMIP 4262 (Figure 17). 
There is no obvious change in direction of growth of the last whorl, so it is uncertain 
whether or not these are mature shells. No obvious apertural modifications are present, 
although in paratype LACMIP 4262 the umbilicus appears to grade into a transverse 
basal groove like that characteristic of many New World Camaenidae (Solem 1978). 

The suture is well marked, and below the suture the whorls show a narrow, steplike 
shoulder with a rounded outer edge. The shoulder is particularly evident on the internal 
molds, reflecting a general thickening of the shell toward the suture, but it is not solely 
an internal feature, also being present where shell material and external sculpture are 
preserved. Shell dimensions are summarized in Table 1 . 

The two referred specimens are internal molds with impressions of external sculp- 
ture in a matrix of light grayish tan lithic wacke. Their maximum diameter, with some 
deformation, is 30-35 mm. One has slightly more than five whorls; the other lacks the 
upper spire and the whorls cannot be counted. The better-preserved specimen shows 
clearly the sculpture of radial riblets, the narrowly shouldered whorls, and the umbilicate 
base of [C] stocki. The body whorl is weakly dilated just behind the aperture and the 
peristome appears to have been moderately turned outward. 

Discussion.— Tho. evidence for taxonomic assignment of [Camaenidae] stocki is 
less satisfactory than that in the preceding cases. Finding of adult specimens with more 
shell material and the adult aperture preserved would greatly improve matters. 

Hanna (1934) originally assigned the species to Helminthoglypta with doubt, al- 
though remarking that the essential characters of that genus were apparent. The only 
living species compared was the large form described about the same time as Hel- 
minthoglypta tudiculata rex Church and Smith, 1938. In 1933, Hanna had been one 
of the collectors of the type lot of that Holocene subspecies. Now known as H. allyniana 
rex, it has a much more depressed shell, with whorls expanding more rapidly, and the 
malleated sculpture typical of the H. tudiculata group of taxa. The umbilicus is narrow 
and almost covered by the expanded inner lip. The suture is moderately impressed; 
there is no trace of the narrow shoulder evident in [C] stocki. 

As noted above, Helminthoglypta includes a wide range of shell shapes. In no 
species, however, is there a narrow, steplike shouldering of the whorl below the suture. 

The sculpture in Helminthoglypta consists of simple growth lines, malleation, 
papillae, or close, regular axial ribbing that is broken into granules by oblique, diverging 
grooves. Often more than one of these types of sculpture are present on the same shell. 
Raised axial riblets like those of [C] stocki are not known in Helminthoglypta. 

No other extant genera of Helminthoglyptidae match any better. Among large, 
globose or trochoid forms, Humboldtiana Ihering, 1892, has rapidly expanding whorls 
sculptured with coarse, granulose wrinkles. Lysinoe Adams and Adams, 1855, has 
sculpture of fine, discrete papillae on an otherwise smooth shell, or a malleated surface; 
its whorls are unshouldered and expand at a greater rate. Monadenia includes smooth 
shells and ones with strong, persistent papillation. The larger species of Leptarionta 
Fischer and Crosse, 1870, have a glossy or silky surface with growth lines scarcely 
evident in relief Polymita Beck, 1837, likewise consists of smooth-shelled species. 

The only modern genus of Helminthoglyptidae that shows comparable sculpture 
in some species is Hemitrochus Swainson, 1 840, of southern Florida and the Antilles. 
Species of Hemitrochus have medium-sized to small, compact shells, often with a 
narrow, obliquely entering umbilicus. The shell of [C] stocki is much larger than any 
of these, and the umbilicus seems to have been broadly open. 



212 



The American camaenid genus Polydontes Montfort, 1810, and the Australian 
camaenid genera Xanthomelon Martens in Albers, 1860, Thersites Pfeiffer, 1856, and 
Hadra Albers, 1860, include species that combine in one way or another the features 
of globose shell, slowly expanding whorls, narrow, steplike shoulder with emphasized 
suture, and fine but prominent radial ribbing. Although differing in its shagreened 
microsculpture and the absence of an umbilicus, the Neotropical camaenid Polydontes 
(Liiquillia) luquillensis (Shuttleworth, 1854) is suggestively similar. For the present, 
however, [C] stocki is assigned to family only, not to any specific genus. [Those who 
insist on a generic epithet are, of course, perfectly free to cite this taxon as PolydontesC?) 
stocki. I may be wrong in trying to bend nomenclatural practice in this way to express 
shades of uncertainty. Note that if the taxon had not already been formally named, we 
could simply cite it as "Camaenid, genus and species indet." The binomial system 
forces us to combine the two essentially distinct activities of identification and clas- 
sification. '"Helminthoglypta" stocki (with quotes) is an unsatisfactory form of citation 
because the species is not helminthoglyptid. And the old expedient of naming a new 
genus is not justified by the information available from the specimens.] 

Age and Correlation 

There are no radiometric dates associated with late Eocene terrestrial faunas in 
southern California. Age assignments of the formations that yielded the camaenid land 
snails discussed here are based on stratigraphic relationships to marine beds and faunal 
correlations with fossil mammals from the western interior (Figure 2). 

Correlations of the Ventura and San Diego County Eocene formations are based 
on Golz and Lillegraven (1977), Lillegraven (1979), Givens and Kennedy (1979) and 
information supplied by T. A. Demere {personal communication 1986). Fossil mam- 
mals in the Tapo Canyon Local Fauna indicate correlation with the Myton Member 
("Uinta C" level) of the Uinta Formation of northeastern Utah and with the "Tejon" 
molluscan stage of the Pacific Coast marine megafossil chronology. The vertebrate 
fauna of the Mission Valley Formation is probably correlative with assemblages from 
the type section of the Tepee Trail (=Wagon Bed) Formation in Fremont County, 
Wyoming, the "Uinta B" level of the Uinta Formation, and the "Tejon" Stage. Most 
vertebrate remains from the Friars Formation have been found high in the formation 
and have been correlated with the "Uinta B" level and the "Transition" molluscan 
stage. 

Fossil marine mollusks found in association with Zachrysia fraterna at SDSNH 
loc. 3278 include Ficopsis remondii crescentensis Weaver and Palmer, 1922, Molo- 
pophorus antiquatus (Gabb, 1864), Neverita globosa Gabb, 1869, Eocernina hannibali 
(Dickerson, 1914), ""Spisula"'' bisculpturata Anderson and Hanna, 1925, and Tellina 
soledadensis. These taxa have stratigraphic ranges that typically overlap only within 
the "Transition" molluscan stage (Givens and Kennedy 1979), indicating that the type 
locality of Z. fraterna is of middle Eocene age (Lutetian; approximately 45-46 Ma 
before present). Flynn (1986) has recently shown that reversed magnetism in the main 
body of the Friars Formation represents magnetic polarity Chron C20R (approximately 
46-48 Ma before present). 

The age of the type locality of Labyrinthus obtusus is less certain. The Tejon 
Formation consists of marine sediments deposited during a major eastward transgres- 
sion during the early, middle, and possibly late Eocene, followed by a westward regres- 
sion in the late Eocene (Nilsen and Link 1 975). The holotype was said to be "embedded 
in the typical hard Type Tejon sandstone with marine forms" in the canyon of Live 
Oak Creek (Anderson and Hanna 1925) but the exact part of the section where it was 
found is not known. Marks (1943) assigned the entire section of the Tejon Formation 
exposed in Live Oak Canyon to the Liveoak Shale Member, which has yielded Ulatisian 
and Narizian (middle to upper Eocene) foraminifers (Nilsen and Link 1975). A more 
recent interpretation of the stratigraphy (Nilsen and Link 1975: fig. 6) indicates that 
the subjacent Uvas Conglomerate Member (containing "Transition" Stage megafossils) 



213 



and the superjacent Metralla Sandstone Member (containing "Tejon" Stage megafossils) 
may be present in Live Oak Canyon as well. In light of its nearshorc deposition and 
abundant megafossils, the Uvas Conglomerate Member may be the most likely source 
of the holotype of L. obtusus (L. R. Saul, personal communication 1987). 

Paleoecology and Paleoclimate 

The average rate of evolutionary change expressed in the shell morphology of land 
mollusks is slow. Many modern genera appear first in upper Cretaceous or Paleogene 
strata with species that are virtually indistinguishable from their living congeners. If 
morphologic change is accepted as a fair sample of total evolutionary change, then land 
snail fossils can be viewed with confidence as indicators of ancient environments (Roth 
1984). 

The present-day climates of Kern, Ventura, and San Diego counties, California, 
are temperate, equable, and summer-dry. At Bakersfield, 50 km north of the type locality 
of Labyrinth us obtusus, the mean annual temperature is 18.4°C and there is a 20.4°C 
annual range of temperature; mean annual precipitation is 16.2 cm, less than 2.0 cm 
falling between May and October (Elford 1970). At San Diego the mean annual tem- 
perature is 17.3°C and the mean annual range is 9.3°C; mean annual precipitation is 
26.4 cm, less than 2.4 cm falling between May and October. At Ventura, the mean 
annual range of temperature is only a few degrees greater; annual precipitation is 36.1 
cm, 1.6 cm falling between May and October. 

In the middle to late Eocene a system of coastal lowlands connected these areas 
and may have communicated with the western interior as well (Lillegraven 1979: fig. 
2b). The San Joaquin Basin was flooded by a major marine transgression, the Transverse 
Ranges did not yet exist as an east-west feature, and the Peninsular Ranges had yet 
to migrate some 365 km northwest along the west side of the San Andreas fault system 
(Link et al. 1979, Lillegraven 1979, Nilsen and McKee 1979). The land mollusks 
indicate that the entire region from present-day Kern to San Diego counties was within 
a single zone of seasonally dry tropical forest. 

Frakes and Kemp's (1972) reconstruction of Eocene global weather patterns (40- 
48 Ma before present) indicates that the southern margin of North America, bordering 
the Caribbean limb of the Tethyan seaway, had a monsoonal climate. The west coast 
of North America had a wet climate and warm marine temperatures. The area was 
free from the upwelling that modulates summer temperatures along the west coast 
today (Scotese and Summerhayes 1986). 

Eocene strata in the San Diego area represent a complex of depositional environ- 
ments including coastal plain, lagoonal, fan-delta, and paralic facies, near the mouth 
of a major river system (Kennedy and Moore 1971, Howell 1975, Link et al. 1979). 
Marine and nonmarine conditions alternated; a coastline was never far away. 

The La Jolla and Poway Groups (which include the Friars and Mission Valley 
Formations) rest unconformably on Cretaceous and older rocks that are weathered to 
a lateritic paleosol. This paleosol probably developed in a humid, tropical climate with 
over 130 cm annual precipitation, an average annual temperature around 20-25°C, 
and lush rainforest vegetation (Peterson et al. 1975). (These authors refer to it as a 
"pre-Eocene" paleosol, but it could equally well be just slightly older than the overlying 
sediments and as young, in part, as middle Eocene.) Both the Friars and Mission Valley 
Formations, however, contain calcareous layers interpreted as caliche deposits. These 
would most likely have formed under semi-arid conditions with annual precipitation 
under 65 cm and seasonally distributed (Peterson et al. 1975, Peterson and Abbott 
1979). Caliches are more common in the Mission Valley Formation than in the Friars 
Formation (Lillegraven 1 979). Apparently middle to late Eocene was a time of transition 
locally from abundant rainfall (as in the modern equatorial belt of lateritic soils) to 
diminished rainfall and seasonal drought. Under the latter conditions the vegetation 
probably resembled modern steppe or savanna, with drought-resistant trees and shrubs. 

Clast-composition of the Ballena Gravels to the east, deposits of the Eocene rivers 



214 



that drained into the San Diego delta (Steer and Abbott 1984), suggests infrequent 
high-energy transport. This is interpreted as the result of major, seasonal flash floods 
in response to tropical storms dropping great amounts of rain on the mountains to the 
east (Lillegraven 1979, Steer and Abbott 1984). For much of the year, however, the 
rivers probably experienced only minor flow. 

Today the native range of Zachrysia is limited to Cuba. Snails of this genus are 
inhabitants of humid and generally rocky forest, where they are found on rocks and 
cliffs, tree trunks, or on the ground (Pilsbry 1929). In typical humid weather they are 
often active by day, crawling on the ground, climbing trees to a height of 2-3 m, or 
wandering over rocks and cliffs. In dry periods they temporarily estivate. Pilsbry's 
(1929) observation that, with the exception of Z. auricoma, Zachrysia do not survive 
for long when confined in a dry box suggests that they have limited ability to resist 
desiccation. 

Zachrysia pwvisoria (Pfeiffer, 1858) and Z. auricoma have been introduced into 
Florida (Pilsbry 1939, Dundee 1974); Z. provisoria, at least, has become established 
in Dade, Monroe, and Broward counties (J. E. Deisler, personal communication 1986). 
Zachrysia provisoria is established as an introduction in the Bahamas (Clench 1952, 
Deisler and Abbott 1984), and Z. auricoma havanensis in Puerto Rico (van der Schalie 
1948). Wurtz (1955) mentioned that the genus had been introduced to the Canal Zone, 
without giving further particulars. The success of these introductions indicates that the 
restriction o^ Zachrysia to Cuba is not merely due to the absence of suitable conditions 
elsewhere. 

The modern range o{ Zachrysia is consistent with (1) tropical climate, equable and 
frost-free but with some winter cooling (Seifriz 1943); (2) precipitation between 80 and 
200 cm annually, ample in summer but with a pronounced winter dry season (Seifriz 
1943, Portig 1976); and (3) forested land, but not necessarily rainforest. The greatest 
diversity of species is recorded in mountainous regions, which are also the wettest areas. 
It is not clear from published collection records whether this is mainly sympatric or 
allopatric diversity. The observations of Pilsbry (1929) and van der Schalie (1948) 
indicate that at least Z. auricoma may tolerate open, drier conditions fairly well. 

At present Labyrinthus has an extensive range from Costa Rica to Peru and the 
Amazon basin of Brazil. Perhaps a third of the species have altitude ranges of more 
than 900 m (Solem 1966). This broad distribution and the scarcity of ecological in- 
formation limit the usefulness of the genus for paleoclimatic interpretation. Material 
collected by Solem (1966) in Panama was taken in "reasonably heavy forest." Baker 
(1926) found Venezuelan species in dense forest under logs and debris or in humus 
near rocky ledges. The geographic range of Labyrinthus is broad enough to take in 
many tropical forest types; at least some of the regions experience a winter dry season. 

The fragile shells of Zachrysia, Labryinthus{l), and the unidentified planispiral 
species from the Friars Formation probably underwent only minimal transport before 
being deposited in a protected, shallow marine setting. They may have been living in 
a humid forest fringing a coastal lagoon. It is less likely that they were caught up in 
flash flooding and transported from the interior. Heavily vegetated coastal belts per- 
sisted into the later Eocene (Lillegraven 1979). In these belts the effects of seasonal 
drought may have been minimized, permitting a diverse land snail fauna to thrive. 

The laterally intertonguing and partly subjacent Scripps Formation, representing 
submarine canyon fill or inner fan deposits (Link et al. 1979), has yielded the proso- 
branch land snail ''Helicina'' dallasi (Hanna, 1926), likewise indicative of tropical 
conditions (Roth and Pearce, in press). 

The Sespe Formation of Ventura County is of fluvial origin and thought to have 
been deposited for the most part near sea level (Lillegraven 1979). Paleoclimatic studies 
are lacking, although time-equivalent marine faunas in the area indicate tropical to 
subtropical marine conditions. If better material of [Camaenidae] stocki confirms its 
similarity to Polydontes luquillensis, then paleoclimatic inferences could be based on 
the study by Heatwole and Heatwole (1978) of P. luquillensis in Puerto Rico. 

The general climatic inferences drawn from Labyrinthus above would also apply 



215 
Zachrysia Polydontes Pleurodonte 




Caracolus 



Labyrinthus- 
Isomeria 



Figure 18. Phylogenetic hypothesis (cladogram) for the genera of American Camaenidae, after Bishop 
(1979), q.v. for pattern of apomorphies. 



to the Kern County setting of L. obtusus. The holotype of L. obtusus was found with 
a marine invertebrate fauna containing species of Ficus, Latirus, Niso, and Pteria — 
genera that today are either exclusively or predominantly tropical in distribution. 

History of the American Camaenidae 

The origin of the Caribbean terrestrial biota has been the subject of considerable 
debate in recent years (Hedges 1983). The principal dichotomy has been between the 
view, on the one hand, that the major events of colonization and radiation occurred 
in post-Oligocene time, predominantly involved over-water dispersal, and can be vi- 
sualized on an essentially modern map of the distribution of land masses (e.g., Pregill 
1981), and, on the other hand, the view that these events took place in the late Mesozoic 
and early Tertiary, predominantly involved vicariance, and require a consideration of 
the distribution of land masses prior to the middle of the Cenozoic Era (e.g., Rosen 
1976, MacFadden 1980). Recent studies of phylogenetically well-understood groups 
contain elements of both sides (MacFadden 1981, Cadle 1985). 

Unlike the marine realm, with its spectacular if not always unequivocal fossil 
record, paleontologic evidence pertaining to the terrestrial debate is extremely sparse. 
Pregill (1981) was able to summarize only about ten instances of vertebrate fossils 
thought to bear on the question (although it is hard to see how some of the Cretaceous 
or Eocene occurrences he cites enable him to reach the conclusion that the groups in 
question arrived in the Antilles no earlier than the medial Tertiary). Land snails may 
prove to have the best fossil record of any terrestrial group. 

A Mesozoic or early Tertiary occurrence of a taxon outside its modern Caribbean 
range disproves a Caribbean origin for that taxon in the later Tertiary. It provides a 
minimum age for the taxon and its sister-group, and likewise for any cladogenetic 
events lower down on the phylogenetic tree of its major group. The fossil occurrence 
of a taxon in North America does not mean that the same taxon was not also simul- 
taneously present in the Caribbean region. For a tropical (i.e., thermally limited) taxon, 
the northern occurrence merely delineates the minimum northward extent of its range 
at the time. The contemporaneous southern, or cquatorward, edge of the range may 
not be discoverable; the terrestrial fossil record in the Neolropics is not particularly 
promising in this regard. My working assumption in such cases is that the range extended 
as far toward the equator as the availability of land would permit. 

Bishop (1979) produced a phylogenetic hypothesis for the American Camaenidae 
(Figure 18) based on the anatomical studies of Wurtz (1955) and summarized the fossil 
occurrences of American camaenids known to him, including a new species of Caracolus 
Montfort, 1810, from the Oligocene While River Group of Nebraska. The fossil evi- 
dence at that time suggested that Caracolus was differentiated in North America by 
the Oligocene at the latest; Pleurodonte Fischer von Waldheim, 1807 (in the broad 



216 



sense, including Pleurodontites Pilsbry, 1939), was differentiated in Florida by the early 
Miocene (the age of the Tampa Limestone); and "differentiation of Polydontes and 
Zachrysia [could] best be understood in terms of modem geography and must post- 
date the period of dynamic geologic change" (Bishop 1979:282). 

Solem (1978) stated that the presence of advanced features of apertural barriers, 
lip sinuation, and body whorl deflection in the Cretaceous and early Tertiary fossils 
Kanabohelix Pilsbry, 1927, and Hodopoeus Pilsbry and Cockerell, 1945, indicated that 
the initial radiation of the Camaenidae was completed by the end of the Mesozoic. He 
noted the resemblance to Isomeria o{ Hodopoeus crassus Pilsbry and Cockerell, 1945, 
and H. hesperarche (Cockerell, 1914), from unknown lower Tertiary localities in the 
American Southwest, but refrained from considering them congeneric because of their 
chronologic and geographic separation. With the recognition herein of Labyrinthus in 
the middle Eocene of California, such conservatism may no longer be necessary. 

Roth (1984) recognized three camaenid genera and subgenera in the upper Eocene 
to lower Oligocene of Trans-Pecos Texas. Pleurodonte (Pleurodonte) and P. {Dentellaria) 
Schumacher, 1817, were sympatric in the Porvenir local fauna (late Eocene) of the 
Vieja Group. Their divergence and the subsequent dispersal that brought about their 
sympatry had already occurred by about 38 Ma before present. An indeterminate 
camaenid that is probably a member of the Labyrinthus-Isomeria lineage was present 
in the Whistler Squat local fauna in the same region of Texas approximately 10 Ma 
earlier. 

The presence of Zachrysia fraterna in the late middle Eocene sets a minimum age 
for the differentiation of Zachrysia. It further sets a minimum age for the dichotomies 
farther down the cladogram: the divergence of the common ancestor of Polydontes and 
Zachrysia from Pleurodonte, and, still earlier, the divergences of the Isomeria- Laby- 
rinthus and Caracolus lineages from the rest of the American Camaenidae. All of the 
earliest appearances of these genera are in North America. 

Figure 1 9 shows the fossil occurrences of these camaenid genera relative to their 
modern distribution, plotted on the geography of middle Eocene time (48 Ma) (Sykes 
et al. 1982). The fossil and modern occurrences are connected by dotted lines— "tracks" 
in the parlance of vicariance biogeography (see Rosen 1 976:432-433 for an explanation 
of method). In every case the tracks connect lower Tertiary localities in North America 
with Holocene ranges in the Caribbean region. 

Except for Miocene Pleurodonte (Pleurodonte) in the Grenadines (Jung 1971) and 
Pliocene or younger P. (Dentellaria) in Jamaica (Bishop 1979), there is very little 
evidence for the timing of events at the southern ends of these tracks. Geological 
reconstructions of the Neotropics have paid little attention to the time when various 
Caribbean lands might have emerged above sea level (Hedges 1983). There is slightly 
better— although still indirect— control on the timing of extinctions in the north. Many 
lines of evidence show that the tropical biota was progressively restricted southward 
as the planetary temperature gradient steepened through the Tertiary (Savin 1977, 
Wolfe 1978). Miocene and later land mollusk faunas of western North America were 
dominantly composed of genera still extant in the region (Roth 1986). 

Even though broadly drawn, these tracks are probably conservative estimates of 
the total ranges of their taxa. They may have overlapped much more extensively; that 
is, there may well have been much more sympatry between different camaenid genera. 
Sympatry of taxa now widely separated has been found repeatedly in Tertiary land 
mollusk faunas of western North America (Roth 1984, 1986). Through the Tertiary, 
the faunal elements came to inhabit different geographic areas. How much of this change 
represents sorting out along environmental gradients and how much represents his- 
torical accident is not clear. What determined, for instance, that Zachrysia should end 
up restricted to Cuba and P. (Dentellaria) to Jamaica? The allopatry on the Greater 
Antilles is all the more puzzling in light of the unusually high sympatric diversity shown 
by the land snail faunas of Jamaica and Hispaniola (Solem 1984). 

The fossil evidence now available supports the model of a variety of camaenid 
genera, well differentiated by the middle Eocene, arrayed across the southern part of 



217 




Figure 19. "Track record" of the American Camaenidae, plotted on map of land-mass distribution for the 
middle Eocene (48 Ma before present) (after Sykes et al. 1982). Dotted lines connect early to middle Tertiary 
occurrences of Camaenid genera with their Holocene ranges. Ca, Caracolus; De, Pleurodonte (Dentellaria); 
La, Lahyrinthus; PI, Pleurodonte {Pleurodonte): Za, Zachrysia. 



North America, roughly parallel to the western limb of the Tethyan seaway. Through 
the Cenozoic, the northern, antitropical, margins of their ranges retreated southward; 
by the Holocene, if not earlier, they had become largely allopatric. 

According to the phylogenetic hypothesis, Zachrysia is one of the most highly 
derived genera of the American Camaenidae; it is also the westernmost. The vicariant 
event that separated Zachrysia from Polydontes may have been related to the late 
Cretaceous or early Tertiary onset of arc volcanism in the American Southwest, east 
of the middle Eocene range o{ Zachrysia (Dickinson 1979: fig. 8; Minckley et al. 1986). 
The phylogenetic hypothesis and the known range of Zachrysia lead to the prediction 
that Eocene species assignable to Polydontes will be found in the southwestern United 
States or northern Mexico, east of the volcanic arc. 

Zachrysia's position as a highly derived "end member" also suggests that any 
ancestral connection with the Australasian branch of the Camaenidae would have been 
eastward, along lands bordering the Telhyan seaway, rather than across the Pacific. 
Through the Eocene and the relevant parts of preceding geologic time, the Indopacific 
Ocean was much wider than today, spanning at least 210° at the equator, while only a 
narrow Atlantic Ocean separated America and Eurasia. The southern coasts of both 
continents lay in a warm and wet, monsoonal climatic belt (Frakes and Kemp 1972). 
The Australian Camaenidae are advanced relative to the southeast Asian members of 



218 



the family; their ancestors entered Australia only after collision of the Australian and 
southeast Asian plates in the Miocene (Solem 1984). Many instances of biotic groups 
with this "interrupted Tethyan" type of distribution are known (Croizat 1964). If the 
American and Australasian camaenid groups are regarded as the two ends of this 
distribution, the prediction follows that fossil forms connecting the American with the 
Australasian Camaenidae will be found in Europe or western Asia. 

Before anyone embarks on an all-out search, however, it would be well to re- 
examine the proposition that the American Camaenidae and the Australasian Ca- 
maenidae compose one monophyletic group and are not simply united by symplesio- 
morphies. 

Acknowledgments 

I am grateful to T. A. Demere, San Diego Natural History Museum, for bringing 
the fossil land mollusks from the Friars Formation to my attention and supplying 
needed information on their geologic setting. D. R. Lindberg helped with the inter- 
pretation of shell structure. R. L. Squires advised on Eocene biostratigraphy. E. C. 
Wilson loaned the type specimens of//.? stocki. J. E. Deisler contributed information 
on the status of introduced Zachrysia in Florida and the Bahamas. Photographs were 
taken in the University of California Museum of Paleontology and the Department of 
Invertebrate Zoology, California Academy of Sciences; the help of Jeanne M. Lynch 
is gratefully acknowledged. I also appreciate the comments of reviewers, named and 
anonymous, including L. R. Saul, G. L. Kennedy, and A. Solem. 

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/^" ^^ TRANSACTIONS 

r/ICZ OF THE SAN DIEGO 

LIBRARY SOCIETY OF 

NATURAL HISTORY 

MAR 7 1988 

HARVARD 
U r ' • Vblume 21 Number 1 3 pp. 221-225 24 February 1 988 

Pseudotealliocaris palincsari n. sp., a pygocephalomorph 
from the Pocono Formation, Mississippian of Pennsylvania 

Frederick R. Schram 

Department of Paleontology'. San Diego Natural History Museum, 
P.O. Box 1390. San Diego. California 92112 USA 

Abstract. Pseudotealliocaris palincsari n. sp., a pygocephalomorph eumalacostracan, is described 
from the Mississippian Pocono Formation of Pennsylvania. This represents an increase in the geographic 
range for the genus. Comparisons are made of the new species to two other recognized species of the 
genus Pseudotealliocaris, P. caudafimbriata and P. etheridgei. 

Introduction 

The Pygocephalomorpha are among the most common of eumalacostracan crus- 
taceans preserved in the nearshore and brackish water communities of the Late Paleo- 
zoic (Schram 1981). Among these, the genus Pseudotealliocaris Brooks 1962 seems to 
be one of the more important. It forms an important component of the Visean nearshore 
marine community of the British Isles (Schram 1979, 1981), and is one of the more 
commonly encountered crustaceans in the Upper Carboniferous deposits of Nova 
Scotia (Copeland 1957). 

The material described here comes from a bore hole drilled by the Pennsylvania 
Department of Natural Resources. This Pseudotealliocaris is the only fossil material 
found in the core sections referred to me for study. This report represents an extension 
of the geographic range of the genus Pseudotealliocaris into the United States. 



Systematic Paleontology 

Order Pygocephalomorpha Beurlen, 1930 

Family Pygocephalidae Brooks, 1962 

Pseudotealliocaris Brooks, 1962 

Type species.— Pseudotealliocaris caudafimbriata (Copeland) 1957. 

Diagnosis.— CdiVdip^iCQ as wide as long, antero-lateral spines large and prominent, 
mid-dorsal keel or ridge present, lateral carinae or ridges two in number. Telson with 
prominent mid-dorsal ridge, with lateral sculpting of the margin to accommodate the 
large lobate caudal furcae. 

Remarks.— The least reliable of the above characters is that which refers to the 
length and width of the carapace. This ratio, of course, is subject to the vagaries of 
preservation and compression. However, all previous authors who have dealt with the 
genus mention this feature. To be able to assess this feature in the way most authors 
have done requires that the branchiostegal areas of the carapace be spread laterally in 
a manner quite atypical of what its position must have been in life. 

Pygocephalomorpha is treated here as an order, as suggested by the cladistic anal- 
yses of Schram (1984, 1986). The exact relation of the pygocephalomorphs to the other 
"mysidacean" orders is still the subject of some speculaton. 



222 




Figure 1. Pseudotealliocahs palincsari, n. sp. (A) SDSNH 26262, holotype, x5.3. B, C. SDSNH 26271a, 
paratype, (B) cephalothorax, x 10.8, (C) antennules (a,), antennae (a.), scaphocerite (sc), antennule pendun- 
cular segments (1-3), base of rostrum (r), anterolateral spine of carapace (als) x27.0. (D) SDSNH 26272a, 
paratype, tailfan, sixth pleomere (P6), uropodal protopod (pr), uropodal exopod (ex), uropodal endopod (en), 
telson (t), primary furca (f,), secondary furca (fj), terminal spine (s), x 19.0. 



Pseudotealliocaris palincsari, new species 
Figures 1, 2 

//o/o?y;7^.- SDSNH 26262 (Figure lA). 

Additional material. -SDSNH 26261, 26263-26272. 

Locality. —Bore hole number 6, Pennsylvania Department of Natural Resources; 



223 




Figure 2. Pseudotealliocaris palincsari reconstruction. Scale represents 5 mm. 



depth 607-613 ft.; 41°12'57"N, 78°55'16"W, PA miles northwest of Aliens Mills, War- 
saw Township, Jefferson Co., Pennsylvania. 

Stratum.— Lower Pocono Formation, Kinderhookian, Mississippian. 

Diagnosis. —Cuticle smooth. Carapace with weakly-developed cervical grooves and 
mid-dorsal ridge, inferior lateral ridges located close to lateral margins, lateral margins 
not serrate. Rostrum of moderate size and slightly falciform, base delineated by grooves. 
Telson with terminal spine. 

Etyinolog)'. —Named in honor of my former professor. Dr. Edward Palincsar, 
Loyola University of Chicago. 

Description.— The cuticle is smooth, without any pits or papillae. The carapace 
(Figure IB) is marked with a weakly developed mid-dorsal ridge. The lateral ridges are 
robust, though the inferior lateral ridges are located close to the lateral margins. The 
posterior and lateral margins of the carapace are marked by furrows, and the posterior 
margin is markedly concave. The cervical grooves of the carapace are weakly developed, 
and lie less than Va the total carapace length from the anterior margin. The rostrum is 
short (less than V^ the length of the carapace), somewhat falciform, with its base de- 
marcated by grooves (Figure IC). 

The antennules have a well-developed peduncle of three segments (Figure IC). 



224 



Table 1 . Structural differences noted between the three recognized species of Pseudotealliocaris. 





caudafimbriata 


etheridgei 


palincsari 


Cuticle 


pitted 


pitted 


smooth 


Lateral margins 


serrate 


non-serrate 


non-serrate 


Cervical groove 


■« 'A from anterior 


'/4 from anterior 


-« 'A from anterior 


Rostrum/carapace length 


0.34 


0.32 


0.18 


Rostrum base 


grooved 


no grooves 


grooved 


Abdominal tergites 


median ridge 


strong lateral ridges 


median ridge 


Telson terminus 


7 


lobed 


spined 


Diaeresis 


7 


circular 


sigmoid 


Uropodal rami reinforcing ridges 


prominent 


weak 


prominent on 
endopod only 



The antennae have broad setose scaphocerites (Figure IC), and the flagella are long 
and quite robust. The stalked compound eyes are spherical and only moderate in size 
(SDSNH 26267a). 

The females bear oostegites (SDSNH 26265a, 26270a). 

The abdominal tergites are without decoration except for a faint mid-dorsal ridge. 
The pleura are rounded anteriorly and pointed posteriorly, and are somewhat demar- 
cated from the tergites proper by a very faint groove. 

The telson has a prominent mid-dorsal ridge, and bears deep lateral indentations 
that extend close to the base of the telson and that accommodate the furcae. The telson 
distally bears a ridged spine. The anterior furcae are large, elongate lobes with very 
long setae (Figure 1 D). There is a much smaller secondary set of furcae (SDSNH 26272a, 
Figure ID) located distally on the telson. The uropodal protopods are marked by a 
comma-like ridge on the dorsal surface. The uropodal rami are setose: the exopod has 
a reinforced lateral margin, a faint median ridge, and a sigmoid diaeresis; the endopod 
bears a well-developed median ridge. 

A reconstruction of P. palincsari is offered in Figure 2. 

Discussion 

Three species are now recognized within the genus Pseudotealliocaris. In addition 
to P. palincsari, there is also P. caudafimbriata (Copeland) 1957, from the Canso Group, 
Namurian, Upper Carboniferous, of Nova Scotia; and P. etheridgei (Peach) 1882 of 
the Tournesian and Visean, Lower Carboniferous, of Scotland and northern England 
(see also Peach 1908). These latter two species o^ Pseudotealliocaris are characterized 
by thin, poorly sclerotized cuticles, which generally are preserved rather poorly. The 
exceptional preservation noted for P. palincsari is due to pyrite replacement. 

The morphological differences among the three recognized species are outlined in 
Table 1 . In regard to the location of the cervical grooves, the grooving around the 
rostrum base, median ridge on the abdominal tergites, and the character of the uro- 
pod rami, P. palincsari resembles P. caudafimbriata. Only the probably primitive feature 
of a non-serrate lateral margin on the carapace is shared between P. etheridgei and P. 
palincsari. In addition, P. palincsari is uniquely characterized by the retention of several 
primitive features such as a smooth and unpitted carapace, unpitted abdominal tergites, 
and short rostrum. P. palincsari is apparently specialized in regards to the weak de- 
velopment of the cervical grooves and the styliform terminus of the telson. 



Acknowledgments 

This material was collected by and offered to me for study by Dr. A. D. Glover, 
Head Coal Geologist, Pennsylvania Department of Natural Resources; and was orig- 
inally brought to my attention by Dr. W. D. I. Rolfe, Hunterian Museum Glasgow 
while a visiting researcher at the Field Museum of Natural History in Chicago. Research 
was supported in part by NSF grant BSR 82-12335. The reconstruction was drawn by 
Michael J. Emerson. 



225 



Literature Cited 



Brooks, H. K. 1962. The Paleozoic Eumalacos- 
traca of North America. Bulletins of American 
Paleontology 44:163-338. 

Copeland, M. J. 1957. The arthropod fauna of the 
Upper Carboniferous rocks of the Maritime 
Provinces. Geological Survey of Canada Mem- 
oirs 286:1-110. 

Peach, B. N. 1 882. On a new Crustacean from the 
Lower Carboniferous rocks of Eskdale and Lid- 
desdale. Proceedings of the Royal Society of 
Edinburgh 30:73-91. 

Peach, B. N. 1908. A monograph on the higher 
Crustacea of the Carboniferous rocks of Scot- 



land. Memoirs of the Geological Survey of Great 
Britain, Palaeontology 1908: 1-82. 

Schram, P. R. 1979. British Carboniferous Mala- 
costraca. Fieldiana: Geology 40:1-129. 

Schram, F. R. 1981. Late Paleozoic crustacean 
communities. Journal of Paleontology 55:126- 
137. 

Schram, F. R. 1984. Relationships within eu- 
malacostracan Crustacea. Transactions of the 
San Diego Society of Natural History 20:301- 
312. 

Schram, F. R. 1986. Crustacea. Oxford Univer- 
sity Press, New York, pp. 1-606. 




..^yr TRANSACTIONS 

LIBRARY OF THE SAN DIEGO 

SOCIETY OF 
^, .^,^,-, NATURAL HISTORY 

MAR V 1983 

HARVARD 
UNIVERSITY 

Volume 21 Number 14 pp. 227-244 24 February 1988 

A new species of hagfish, genus Eptatretus (Cyclostomata, Myxinidae), 
from the Pacific Ocean near Valparaiso, Chile, with new data on 
E. bischojfii and E. polytrema 

Robert L. Wisner and Charmion B. McMillan 

Marine Biology Research Division, A-002, Scripps Institution of Oceanography, 
La Jo/la, California 92093 

Abstract. — A new species of hagfish of the genus Eptatretus, E. nanii, is described from the Pacific 
Ocean near Valparaiso, Chile, and a key to the eastern South Pacific species is given. New data are 
presented for E. polytrema and E. bischoffii. A neotype is designated for E. polytrema. The extensive 
use of the name polytrema for polybranchiate mixinids from the Chilean area is clarified. 

The efferent duct of the posteriormost left gill pouch is separate from that of the pharyngocutaneous 
duct in 100% of £■. bischoffii, in 61% of £■. nanii, and in 9% of £■. polytrema, but almost never in other 
known species of Eptatretus. 

Resumen. — Se describe una nuevo especie de babosa de mar del genero Eptatretus, E. nanii, 
obtenida en el Oceano Pacifico cerca de Valparaiso, Chile, y se incluye una clave de identificacion de 
las especies del Pacifico sureste. Se presentan nuevos datos sobre las especies E. polytrema y E. bischoffii. 
Se designa un neotipo para E. polytrema. Se aclara el uso del nombre polytrema para mixinidos 
polibranquios del area chilena. El ducto eferente del saco de la ultima branquia izquierda posterior esta 
separado del bolsillo del ducto faringocutaneo en 100%, 61% y 9% de los individuos de las especies E. 
bischoffii, E. nanii y E. polytrema, respectivamente, caracteristica muy raramente encontrada en las 
otras especies de Eptatretus. 

Introduction 

Hagfishes are primitive eel-like agnathous vertebrates that are cartilaginous, en- 
tirely marine, and bottom dwelling. They lack jaws, have three paired sets of sensory 
barbels around the mouth and feed on invertebrates and dead or moribund fishes. Two 
sets of keratinous teeth (cusps), one on each side of the mouth, are attached to dental 
plates, which in turn attach to the anterior end of the dental muscle, a sub-cylindrical 
complex of muscles and cartilages (the club-shaped muscle, lingual muscle, or great 
muscle mass, of authors) which laterally evert and retract the two sets, providing a 
biting-cutting mechanism for feeding. Hagfishes are essentially blind, with rudimentary, 
light sensitive eyes embedded in the flesh of the head and covered with integument 
usually less pigmented than the surrounding tissue especially in the genus Eptatretus, 
but not in the genus Myxine. Internal gill pouches are supplied with water entering the 
nasopharyngeal aperture above the mouth and by a velum in the pharynx which acts 
as a pump. Discharge (posteriorly) is via one or more pairs of adjacent openings to the 
exterior (branchial apertures) and the pharyngocutaneous duct, an enlarged opening 
confluent with or contiguous to the last (or only) aperture on the left side. There is a 
row of internal, mucus-secreting (slime) glands and associated external pores, usually 
one per body segment, on each side. Habitat is usually soft mud at depths of 10 to 
2000 m. In colder waters some species live in shallow depths (5 m) and among rocks. 

Six genera of myxinoids, totalling about 37 species (about 15 in the genus Epta- 
tretus), are currently recognized but the alpha taxonomy is uncertain due to a paucity 
of collections and lack of published data. In addition, three new species o^ Eptatretus 
and one oi Myxine are being described (Wisner and McMillan, in prep.). 



228 



This study of Eptatretus from the Pacific Ocean near Valparaiso, Chile, is one of 
a series resulting from specimens and data largely accumulated under the direction of 
the late Carl L. Hubbs. Herein we describe a new species, E. nanii, and present new 
data on E. polytrema (Girard 1854) and E. bischoffii (Schneider 1880). As the putative 
type specimen of £". polytrema (USNM 78530) differs from Girard's description, and 
cannot in fact be the holotype, we designate a neotype (SI084-243) for E. polytrema 
in order to stabilize that name. Also, we clarify the use of the species name polytrema. 
Confusion has arisen because most polybranchiate hagfishes collected near Valparaiso 
have been placed in synonymy with Bdellostoma polytrema Girard (1854:199; 1855: 
252-253, pi. 3, figs. l-5b). We also make a nomenclatural correction of the gender 
ending of the species name Eptatretus laurahubbsae McMillan and Wisner 1984 in 
accordance with Article 31 a ii of the International Code of Zoological Nomenclature. 

Abbreviations. —FCD: external opening of the pharyngocutaneous duct; ordinarily 
confluent with the posteriormost left gill aperture, and much larger than all other 
apertures. 

GA: gill (branchial) aperture; external opening of the efferent duct leading from a 
gill pouch. 

GP: gill pouch; rounded, serially arranged structures along and posterior to the 
dental muscle. 

DM: dental muscle; the firm, elongate, cylindrical complex of muscles and cartilages 
that moves the dental plates and sets of cusps during feeding. Posterior portions of 
DM are shown in Figure 3 lying between the rows of gill pouches. 

VA: ventral aorta; the portion between the heart (ventricle) and where it branches 
to each side of DM. 

ABA: afferent branchial artery; one of the small blood vessels that lead to each gill 
pouch from VA or its branches. 



Methods and Materials 

Methods of measuring and counting are essentially those reported by McMillan 
and Wisner (1984) with the following modification: In the present study we use only 
the midline incision (of the two incisions for cusp study discussed previously) which 
is faster and does much less damage to the specimen. There is almost no bilateral 
variation in counts, thus any confusion caused by the "reverse image" would be in- 
significant. It is essential to continue the midline incision posteriorly to slightly past 
the branchial openings in order to make an accurate count of the gill pouches and 
observe their relationship to the dental muscle and ventral aorta. 

Due to variability in confluence in external discharge of the efferent duct of the 
last gill pouch, left side, and the opening of the pharyngocutaneous duct, we have given 
only the count for gill pouches (Table 1). Thus for E. polytrema the total of exterior 
openings (left side) would range from 1 3 to 15, but the range 1 3-14 in Table 1 represents 
the actual number of gill pouches. 

Features used in counts and measures are shown in Figure 1 and abbreviations 
are identified in Figures 2 and 3. 

As stated by McMillan and Wisner (1984:251, 255), the external opening of PCD 
ordinarily is confluent with that of the posteriormost left GA and the number of internal 
GP usually is the same as that of the GA with only slight variation. Normally, PCD 
is included in the count of the left GA. However, in our material, there is considerable 
variation in the relationships of the last GA and PCD. In all 35 specimens of £". bischoffii 
examined by us the two are separate. Often the last GA is a narrow slit very closely 
adjacent to PCD, but it retains its own efferent duct to the exterior from the last GP. 
In E. polytrema, seven of 18 specimens (39%) have the efferent ducts of the last GP 
and the PCD confluent, and in E. nanii, 20 of 22 specimens (91%) those of the last 
GP and PCD are confluent. 

Such variation presents problems in counting the GA. The PCD of E. bischoffii 



229 



Table 1 . Number of gill pouches, prcbranchial, branchial, trunk, tail, and total slime pores for three species 
of hagfishes (genus Eptatretus) from the Pacific Ocean near Valparaiso, Chile. Counts for E. polytrema 
and E. nanii include those for left and right sides; counts for E. bischoffii represent the left side only. 
(Values for type specimens are indicated by an asterisk.) 















Gill pouches 














10 


11 


12 


13 


14 










n 


X 


a 


E. polytrema 
E. nanii 
E. bischoffii 


63 


7 


12 


12 
35* 


24* 










36 
47 
70 


13.67 
\1.1A 
10.10 


0.47 
0.44 
0.30 














Prebranchial slime 


pores 












6 


7 


8 


9 


10 


11 12 


13 


14 


15 


n 


X 


a 


E. polytrema 
E. nanii 
E. bischoffii 


8* 


10* 


13 

7 


1 
18* 


14* 

1 


2 1 
8 16 


8 


1 


1 


32 
42 
35 


1.11 

9.33 

12.09 


0.86 
0.89 
0.96 












Branchial slime pores 












6 


7 


8 


9 


10 


11 12 


13 


14 




n 


A' 


a 


E. polytrema 
E. nanii 
E. bischoffii 






1 


32 


1 


1 7 
8* 30* 

1 


23* 
3 


3 




34 
41 

35 


12.82 

11.88 

9.06 


0.62 
0.50 
0.41 














Trunk slime pores 












38 


39 


40 


41 


42 


43 44 


45 


46 


47 


n 


A' 


(J 


E. polytrema 
E. nanii 
E. bischoffii 


1 


5 
5 


10* 
5 
3 


7 
7 
5 


7 

10 
5 


2 2 
7 6* 
6 9 


1 
3 

1 


1 
2 


1 


34 
46 
31 


41.03 

Aim 

41J7 


0.15 
0.20 
0.16 














Cloacal slime pores 












2 


3 


4 


5 












n 


X 


ff 


E. polytrema 
E. nanii 
E. bischoffii 


1 


5 
28* 
14 


26* 
14* 
16 


3 

2 












34 
42 
33 


3.94 
3.33 
3.58 


0.48 
0.47 
0.65 










Caudal slime pores 












7 


8 


9 


10 


11 


12 13 








n 


X 


(T 


E. polytrema 
E. nanii 
E. bischoffii 


1 


2 
2 


4 
6 
9 


11* 

25 
15 


12* 
8* 

7 


5 

2 1 








34 
42 
34 


10.41 

9.88 

10.15 


0.11 
0.85 
0.97 














Total tail pores 












11 


12 


13 


14 


15 


16 17 








n 


-Y 


a 


E. polytrema 
E. nanii 
E. bischoffii 


2 


1 
5 

1 


5 

19 
9 


14* 
15* 
18 


10* 
1* 
3 


3 1 

2 








34 
42 
33 


14.35 
13.19 
13.88 


1.03 
0.85 
0.84 














Total sli 


ime pores 












72 


73 


74 


75 


76 


77 78 


79 


80 


81 82 83 n 


.V 


a 


E. polytrema 
E. nanii 
E. bischoffii 


2 
1 


4* 
2 


3 

5 

2 


10 
5 
1 


4* 
10 
■5 


2 4 
5 1 
8 5 


4 

6* 

4 


2* 
3 


3 
3 


33 

1 41 

1 32 


75.58 
76.71 
77.84 


2.04 
2.44 
2.06 



does not represent a GA and normally would not be counted. But, in E. nanii the last 
GA is seldom separate from the PCD (two of 22 specimens), and for practical purposes 
the PCD may be included in the count of GA. The high incidence of non-confluence 



230 





Figure 1 . Outline of a hagfish {Eptatretus) showing regions and features used in measuring and counting: 
A-H, total length (TL); A-B, prebranchial length; B-C, branchial length, including gill apertures (GA); D, 
external opening of pharyngocutaneous duct (PCD); E, ventral finfold; C-F, trunk length; F, origin of cloaca; 
G, caudal finfold. The linear series of dots represents the prebranchial, trunk, and cloacal-caudal (tail) slime 
pores. 




Figure 2. Branchial area (E. bischoffii), showing features discussed in text: A, pharynx; B, afferent duct and 
gill pouches (GP); C, afferent branchial artery (ABA); D, left branch of ventral aorta; E, efferent duct from 
last gill pouch; F, ventral aorta (VA), very short in E. bischoffii; G, duct leading from pharynx to external 
opening (PCD); H, ventricle (V). Dental muscle (DM) not shown. 



231 




A 



B 



C 



Figure 3. Branchial areas, showing arrangements of DM, VA, and GP in: A, E. polytrema; B, E. nanii; 
C, E. bischoffii (DM often overlies VA). DM is the cylindrical mass lying between the rows of gill pouches. 



(61%) in E. polytrema means that counts will often be inaccurate. An accurate count 
requires dissection and examination of the efferent ducts on the left side. 

Head grooves.— Ayers and Worthington (1907:331, figs. 5-10) referred to lines in 
the skin of the head near the eyespots of Bdellostoma Dombeyi {^Eptatretus stoutii 
(Lockington 1878)] as lateral line canals. McMillan and Wisner (1984:255) used the 
term sensory canals in reference to these lines. In a study we had overlooked, Bullock 
et al. ( 1 982) found no electroreceptive capacity in E. stoutii. Fernholm (1985) examined 
the lateral line systems of cyclostomes by transmission electron microscopy and found 
that there are no canals in E. stoutii or E. burgeri and that the lines are non-innervated 
grooves containing no neuromasts; he referred to the lines as lateral line grooves. We 
accept this evidence as lack of sensory capacity and adopt the term "head grooves" in 
lieu of sensory canals. 

Head grooves of the three species treated here are very similar in size, number, 
and arrangement to those shown by McMillan and Wisner (1984, fig. 4) and by Ayers 
and Worthington (1907, figs. 5-6) for other species of Eptatretus. In no species did a 
groove extend across the dorsal midline. 

Collection data and disposition of specimens examined in this study are listed in 
the treatment of each species. Institutions which have furnished study material, or in 
which type specimens have been deposited, are: Scripps Institution of Oceanography, 
La Jolla, California (SIO); California Academy of Sciences, San Francisco, California 
(CAS); Natural History Museum, Los Angeles County, Los Angeles, California (LACM); 
National Museum of Natural History, Washington, D.C. (USNM); Museo Nacional 
de Historia Natural, Santiago, Chile (MNHNC); Zoological Institute, Academy of 
Sciences, Leningrad, USSR (ZIL); Gulf Coast Research Laboratory, Ocean Springs, 
Mississippi (GCRL). 



232 



Discussion of synonymies.— TYvq problem of including PCD in the count for GA 
affects the construction of meaningful synonymies for E. polytrema and E. nanii. Only 
two authors who may have had these species (Dean 1903, Buzeta 1964) included 
remarks on color, and only seven gave counts of 14 gill apertures. The color notes 
almost certainly pertain to E. polytrema. No author stated that the PCD was included 
in the count for GA. 

An accurate synonymy may be available only for E. bischoffii, based on stated 
counts of 10 GA. Other authors apparently followed Regan (1912) who gave 10 GA 
for Heptatretus decatrema, and used the name decatrema under various genera. Un- 
fortunately, Regan (1912) gave no counts of GA, or indication of having counted them. 
We must assume that these authors merely followed prior references. Thus, the citations 
are not includable in an accurate synonymy. 

Since none of the 47 individuals of £". nanii examined have 14 GA, all references 
stating 14 GA are placed in the synonymy of £". polytrema. We find no statements of 
numbers of GA other than 14. Only one questionable reference (Perez Canto 1912) 
may pertain to E. nanii (13 GA). 

Of a total of 8 1 citations listed here dealing with polybranchiate myxinids from 
the coast of Chile, only 22 (32%) included information on counts of GA or color notes, 
and can be placed in the synonymies of E. bischoffii or E. polytrema. The remaining 
59 citations are listed separately under the heading of "Unassignable Records." 

Key to Species of Eptatretus of the Eastern South Pacific Ocean 

la. Gill apertures seven. Two (rarely three) fused cusps on anterior, and three on 

posterior multicusps. Total slime pores 97-105 

E. laurahubbsae McMillan and Wisner 1 984 

lb. Gill apertures 9-15. Always three fused cusps on anterior and posterior mul- 
ticusps. Total slime pores 68-86 2 

2a. Prebranchial and tail lengths each greater than branchial length. Posteriormost 
gill aperture (left side) separate from, but closely adjacent to, pharyngocuta- 
neous duct. Gill apertures 10 (9-11). Ventral finfold absent or scarcely de- 
veloped E. bischoffii (Schneider 1 880) 

2b. Prebranchial and tail lengths each less than branchial length. Posteriormost 
gill aperture (left side) widely separate from pharyngocutaneous duct. Ventral 
finfold absent to well developed. Gill apertures 12-15 3 

3a. Color variably piebald over a dark background. Prebranchial slime pores 7- 
8 (6-9). Gill apertures 14(13-15). Ventral finfold varying from absent to well 
developed E. polytrema (Girard 1 854) 

3b. Color black or dark purplish-brown, not piebald. Prebranchial slime pores 9- 
10 (8-12). Gill apertures 13 (12-14). Ventral finfold absent or vestigial .... 
E. nanii, new species 

Although the characters, singly or in combination, of the three species discussed 
below {E. laurahubbsae will not be further discussed), are adequately expressed in the 
key to species, there is slight to considerable overlap in most counts and body pro- 
portions. There is, however, no overlap in numbers of gill pouches between E. bischoffii 
and the other two species (Table 1 ), and all three show no overlap in numbers of gill 
pouches in positions relative to DM and VA (Table 3, Area III). 

The three species of the polytrema complex maybe distinguished by meristic char- 
acters. There are significant {P > .001) differences in numbers of gill pouches, slime 
pores, and teeth (Tables 1 and 2). The ranges of gill pouches for E. polytrema and E. 
nanii (12-14) do not overlap with that of £". bischoffii and the means for E. polytrema 
and E. nanii (13.67 and 12.74 respectively) differ. Similarly, E. bischoffii can be dis- 
tinguished from the other two species on the basis of mean numbers of prebranchial 
and branchial slime pores and anterior unicusps. Eptatretus nanii and E. polytrema 
differ in mean numbers of prebranchial slime pores, anterior unicusps and total cusps. 

The greatest differences in body proportions lie in E. bischoffii having the pre- 



233 



Table 2. Number of unicusps in the anterior and posterior sets of cusps, and of total cusps, of three species 
of hagfishes (genus Epiairciiis) from the Pacific Ocean near Valparaiso, Chile. (Values for type specimens 
are indicated by an asterisk.) 















Anterior unicusps 
















7 


8 


9 


10 


11 


12 










/; 


.V 


a 


E. polytrema 
E. nanii 
E. b i sell off li 


1 


3 

7 


29* 

1 
53 


3 
14 

5 


26* 


3 










35 
44 
66 


9.00 

10.70 

8.94 


0.41 
0.62 
0.49 














Posterior unicusps 
















7 


8 


9 


10 


11 












n 


A' 


a 


E. polyirema 
E. nanii 
E. bischoffii 


1 


2* 
3 
11 


29* 
23* 
45 


4 
17 
10 


1 












36 
44 
66 


9.00 
9.36 
8.98 


0.53 
0.64 
0.56 
















Total cusps 
















44 


45 


46 


47 


48 


49 


50 51 52 


43 


54 


55 


n 


A' 


a 


E. polytrema 
E. nanii 
E. bischoffii 


2 


1 


2 


4* 

5 


10 
17 


1 
2 

4 


1 1 

1 6 5* 

1 1 1 


3 


4 


1 


18 
22 
33 


47.94 
52.00 
47.88 


1.22 
1.60 
1.53 



branchial and tail lengths each greater than the branchial length. The reverse occurs in 
E. nanii and E. polytrema. All other proportions of the three species are very similar. 
Body color is useful in separating the three species: E. polytrema is notably piebald 
(Figure 4); E. nanii is uniformly black or very dark-purplish brown; E. bischoffii is dark 
with randomly scattered minute pale spots and areas, primarily in the anterior ventral 
region. 




Figure 4. Contrast in piebald color patterns in E. polyirema. The two specimens were taken together 
(SI072-148). 



234 



Table 3. Number of GP (both sides included) in positions relative to DM and VA in Eptatretus polytrema, 
E. nanii, and E. bischoffii. AREA I— anterior to tip of DM; AREA II — between tip of DM and branching 
of VA; AREA III — VA posterior to branching. Boundaries of AREAS I, II, III are indicated in Figure 3. 








1 


2 


3 


4 


5 6 


7 


8 


9 


10 


n 


X 


(J 














AREA I 
















E. polytrema 












1 7 


6 


21 


9 


6 


50 


7.96 


1.23 


E. nanii 










3 


17 15 


1 








36 


5.39 


0.68 


E. bischoffii 










4 


3 5 
AREA II 


12 


9 


9 


14 


56 


7.82 


1.82 


E. polytrema 


4 




9 


21 


8 


7 1 










50 


3.08 


1.34 


E. nanii 


1 


24 


9 


2 














36 


1.33 


0.62 


E. bischoffii 


12 


11 


9 


12 


5 


4 3 
AREA III 










56 


2.20 


1.76 


E. polytrema 




3 


26 


13 


8 












50 


2.52 


0.83 


E. nanii 












4 16 


13 


1 


2 




36 


6.47 


0.93 


E. bischoffii 


56 




















56 


0.00 


0.00 



Systematics 

Eptatretus nanii, new species 

Homea polytrema. Perez Canto 1912:1230, 1238 (anguilla negra; Bahia de Arauco, coast of 
Anconcagua [E. nanii presumed]. 

Holotype.—Sl065-675, female, 609 mm TL, taken about 33.4 km seaward of 
Valparaiso, Chile, in a commercial shrimp trawl at 274 m, 22-23 December 1965. 

Pamtypes.—Sl065-675, female and three males, 510-593 mm TL, taken with the 
holotype; SI08 1-104, mature female, 664 mm TL, taken at 350 m (no other data); 
SI084-244, male, 541 mm TL, taken near Valparaiso, Chile, between 100 and 250 m 
(no other data); SIO85-60, female, 561 mm TL, taken at 33°09'S, 7r51'W, in a 72 ft 
shrimp trawl between 170 and 180 m, 1 August 1966; CAS 5612, two females, 486 
and 590 mm TL, taken at 33°22'S, 7r52'W, in a 72 ft shrimp trawl between 260 and 
270 m, 1 August 1966; LACM 43776-1, two, 570-640 mm TL, taken at 33°09'S, 
7r51'W, in a 72 ft shrimp trawl between 170 and 180 m, 1 August 1966; USNM 
272583, 6 specimens, 450-610 mm TL, taken at 33°09'S, 7r21'W, in a 72 ft shrimp 
trawl between 170 and 180 m, 1 August 1966; GCRL 12464, mature female, 619 mm 
TL, found in a fish-meal plant, San Antonio, Valparaiso Bay, Chile, 21 March 1974; 
MNHNC (S) P. 6378, male, 6 14 mm TL, taken at 35°26.5'S, 73°01 'W, in a 72 ft shrimp 
trawl between 290 and 450 m, August 1966; MNHNC (S) P. 6381, male, 570 mm TL, 
taken at 28°03'S, 7ri5'W, at 505 m, 16 January 1981; MNHNC (S) P. 6382, mature 
female, 600 mm TL, taken at 36°07.3'S, 73°05'W, in a shrimp trawl at 301 m, 20 April 
1983. 

Distribution.— Al\ specimens were taken between Valparaiso, Chile, south to 
36°26.5'S, 73°05'W, at depths ranging between 100 and 470 m. E. nanii was taken 
once with E. polytrema at 33°22'S, 7r52'W, in a 72 ft shrimp trawl between 260 and 
270 m. 

Diagnosis.— External apertures 13, 13 (13-14); gill pouches 13, 13 (12-13). Body 
robust, deepest at about midlength. Branchial length greater than either the prebranchial 
or tail lengths. Three fused cusps (multicusps) on both the anterior and posterior sets 
of cusps. Color black or very dark purplish-brown with no indication of pale markings. 
Ventral finfold variably absent to vestigial. Head grooves present near eyespots. Efferent 
duct of last GP, left side, confluent with that of PCD in 91% of specimens (20 of 22). 

Etymology.— Wq are pleased to dedicate this species to Professor Alberto Nani 
Caputo, formerly of the Department of Oceanography, University of Chile, Vifia Del 
Mar, for his early work on the Myxinidae of Chile, for his considerable aid to us via 
correspondence with Carl L. Hubbs, and for providing specimens. 



235 



Table 4. Averages and ranges (in thousandths of total length) of selected body proportions for three species 
of hagfishes (genus Eptatretus) from the Pacific Ocean near Valparaiso, Chile. *Finfold measureable on 
only 7 of E. polytrema and 6 of E. nanii. 



n. size ranges (mm) 



19 (289^60) 

E. polytrema 

Mean av. (range) 



22 (446-664) 

E. nanii 

Mean av. (range) 



34 (210-680) 

E. bischoffii 

Mean av. (range) 



Preocular length 

Prebranchial length 

Branchial length 

Trunk length 

Tail length 

Tail depth 

Body depth excluding finfold 

Body depth including finfold 

Body depth at cloaca 

Length of dental muscle 



55 (44-67) 
155 (139-169) 
182 (168-201) 
499 (478-530) 
152(127-179) 
71 (57-86) 
89 (68-109) 
90(68-109)* 
62 (49-80) 
262 (228-305) 



51 (40-61) 
144(128-156) 
192 (175-220) 
504 (475-529) 
162(152-173) 
79 (62-92) 
84 (73-99) 
89 (73-102)* 
60 (42-76) 
222 (202-260) 



58 (40-66) 
202(176-224) 
135 (114-161) 
499 (450-542) 
168(140-218) 
71 (56-83) 
89 (71-112) 
90(76-112) 
67 (56-87) 
294(251-357) 



Description.— Counts (Tables 1-3) and morphometries (Table 4) are given and 
compared with similar counts for E. polytrema and E. bischoffii. Body robust, deepest 
at about PCD, increasingly laterally compressed toward tail; greatest width about 70% 
of greatest depth. Ventral finfold absent or vestigial, usually present only as a thin, pale 
line originating at about anterior 40% of TL and ending at cloaca. In a few specimens 
the finfold is about 1 mm high. Tail spatulate, its ventral outline nearly straight, its 
depth 1.3 (1.0 to 1.6) times body depth at cloaca, its length about 16% (15-17%) of 
TL, and slanting downward from cloaca. A thin finfold present around tip of tail, ending 
dorsally about over cloaca. A narrow, pale margin present on caudal finfold of many 
specimens; it is absent on the holotype. 

Head at eyespots slightly deeper than wide, narrowing slightly to the rostrum. 
Nasopharyngeal aperture broad, about half the width of head at eyespots. Face sloping 
at about a 45° angle. Eyespots large but margins vaguely defined, minimally contrasted 
with background. First two pairs of barbels about equal in length, each about 70% of 
length of third pair. 

Color very dark brown, almost purplish-black in some specimens; others are a 
lighter brown, but apparently this is an artifact of preservation as data sheets prepared 
in 1971 state "black" for all specimens. No pale spots or areas (piebald condition) 
evident. Gill apertures with pale narrow margins; most slime pores appear whitish at 
centers. Distal half of all barbels whitish. 

Head grooves behind eyespots in all specimens in good condition. They also occur 
before eyespots on most specimens, but often only on one side. The grooves are difficult 
to see, particularly before eyespots, even on only moderately wrinkled specimens. 
Arrangement and number of grooves similar to that of £". polytrema and E. bischoffii. 
From 1 to 5 grooves occur before eyespots and 1 to 7 behind. Most of those before 
eyespots lie along the longitudinal axis; those behind are primarily vertical. 

Length of DM 22% (20-26%) of TL. DM width 16% (13-22%) of its length, its 
depth 57% (45-64%) of its width. VA long, 38% (31-50%) of length of DM, branching 
near tip of DM. An average of 6.4 (4-9) GP lies between ventricle and branching of 
VA, 1 (0-3) lies between branching and DM, and 5.5 (4-7) lie anterior to tip of DM 
(Fig. 3B). 

£■^^5. —Large eggs are present in six females. Total length (TL), numbers of eggs 
and dimensions of the largest egg are given; SI067-675, 593 mm TL, 33, 27.0 by 6.5 
mm; SIO81-104, 664 mm TL, 23, 16.0 by 3.5 mm; SIO85-60, 561 mm TL, 38, 16.5 
by 5.0 mm; GCRL 12464, 629 mm TL (number of eggs not recorded), 24.0 by 5.8 
mm; LACM 43776-1, 582 mm TL, 22, 21.5 by 5.5 mm; USNM 272583, 612 mm TL, 
31, 17.5 by 3.8 mm. Polar caps are well developed but there is no evidence of anchor 
filaments (hooks) at capsule ends of any egg, as shown by Dean (1899:234, figs. 9-18, 
pi. 1 5) and Jensen ( 1 966:90). [This latter reference was incorrectly cited as A. Jespersen, 



236 



1975, by McMillan and Wisner, 1984. Jespersen's study dealt only with spermiogene- 
sis.] An unidentified nematode, about 20 mm long, was coiled among the eggs in a 664 
mm female. 

Food items. —A female, 585 mm TL (SIO85-60), had ingested a juvenile macrourid 
195 mm long. About 35 mm of the long, slender tail protruded from the cloaca. The 
head is missing but the body is relatively intact with minimal damage from digestive 
action. There are no bones in the gut that can be related to the head of a macrourid 
fish; perhaps some predator had bitten off the head and did not ingest the body. It is 
of interest that the fish had been ingested tail first. The only other food item present 
was the posterior portion of a small, shrimp-like crustacean lying anterior to the mac- 
rourid. 

Eptatretus bischoffii (Schneider 1880) 

Bdellostoma polytrema not of Girard. Putnam 1874:160 (10 gills, each side; description; eggs; 
suggests that Girard ( 1 854, 1855) included some mucus pores in his count of 14 gill openings). 

Bdellostoma bischoffii Schneider 1880:1 15-1 16 (original description; 10 gill openings, each side; 
no locality); Plate 1896:16-21, figs. 1-4 (detailed description of eggs presumed to be of this 
species; Talcahuano Bay on mud bottom in 8 fathoms; Coquimbo south to Tierra del Fuego. 

Heptatretus decatrema. Regan 1912:535 (original description; 1 gill openings; Chile; i^^e/Zosromfl 
polytrema (non Girard), Putnam). 

Eptatretus dombeyi (Shaw). Fowler 1940:743, fig. 1:744 (in part; fig. 1, drawing by Richard of 
example from Napon Bay, Valparaiso, Chile, January 28, 1839; 10 gill openings shown). 

Polistotrema polytrema not of Girard. deBuen 1961:105-110 (10(14?) openings; figure from 
Girard 1855; reference to original account and number of gill openings questioned; reddish- 
brown when fresh, dark-leaden in formalin; extensive synonymy; vernaculars; Valparaiso, 
Chile). 

Bdellostoma decatrema. Adam and Strahan 1963; 6(10 pairs of gills; length to 480 mm; Chile); 
Rauther 1924:685 {=B. bischoffii?; 10 gill openings, each side; coast of Chile). 

Polistotrema decatrema. Buzeta 1964:49-58, fig. 1, pi. 1 (in part; material with 9-1 1 gill openings 
only; characters; compared to P. polytrema, with 13 to 14 gill openings; Coquimbo to Puerto 
Montt, Chile). 

Validity of name.— We use the name bischoffii, applied by Schneider (1880:1 15- 
116) to a hagfish with 10 gill openings, presumably from off Southern Chile, despite 
the fact that the name has been used only twice before (Plate 1896:16-21) Rauther 
(1924:685). To our knowledge, this is the only hagfish having 10 gill openings. Ap- 
parently the name was overlooked by Regan (1912:535) when he described Heptatretus 
decatrema new species, characterized in part as having 10 gill openings. Subsequent 
authors have applied a variety of names to this species. Inasmuch as the literature on 
this species is limited, stability is hardly threatened by replacing the specific name 
decatrema by its senior synonym bischoffii. 

Material examined. -S1065-669, female, 276 mm TL, taken at 32°51'S, 72°08'W, 
in a 5 ft Agassiz beam trawl at 30 m, 19 December 1965; SI065-673, two females, 
212 and 31 1 mm TL, taken in Valparaiso Harbor, Chile, in a trap at 30 m, 23-24 
December 1965; SI065-676, female, 244 mm TL, taken in Valparaiso Harbor, Chile, 
in a trap at 30 m, 24 December 1965; SI065-678, two females, 313 and 346 mm TL, 
taken at La Ventana, 30 miles North of Valparaiso, Chile, in a tidepool at 10 m, by 
fish poison, 28 December 1965; SI072-148, five females, 215-580 mm TL, taken in 
Bahia Inglesa, Chile, 27°07'S, 70°55'W, in a trap at 20m, 9-10 April 1972; SI072-149, 
five males, 385-466 mm TL, and five females, 372-590 mm TL, taken in Bahia Inglesa, 
Chile, 27°07'S, 70°55'W, in a trap at 8 m, 9-10 April 1972; SIO72-150, male, 482 mm 
TL, taken in Bahia Inglesa, Chile, 27°07'S, 70°55'W, in a trap at 12 m, 9-10 April 
1972. SI077-94, female, 331 mm TL, taken near Valparaiso, Chile, at 50 m (no other 
data); SI08 1-101, juvenile, 1 13 mm TL, taken at 10 m in a tidepool near Montemar 
Laboratory, Univ. Chile, Vifia del Mar (no other data); SI08 1-102, female, 485 mm 
TL, taken at 6 m, near Montemar Laboratory, Univ. Chile, Vifia del Mar (no other 
data); SI085-12, 9 specimens, 418-605 mm TL, taken in Bahia Concepcion, Isla 
Quiriquiiia, Chile, at 10 m in a net over rocky, algae covered bottom, 5-10 April 1972; 



237 



ZIL 3 14-960, male, 500 mm TL, taken from a dry dock at Talcahuano, Chile. Provided 
by A. P. Andriashev, Zool. Inst., Acad. Sci. U.S.S.R.; PM-4 1 3 (Univ. Austral de Chile), 
juvenile, 320 mm TL, taken at Manquillahue, near Valdivia, Chile, 14 June 1976 (no 
other data); PM-30 (Univ. Austral de Chile), two juveniles, 2 1 and 280 mm TL, taken 
at Mehuin, near Valdivia, Chile, 6 July 1961 (no other data); PM-61 (Univ. Austral 
de Chile), male, 680 mm TL, taken at Mehuin, near Valdivia, Chile, 3 December 1961 
(no other data); USNM 75380, 440 mm TL, sex unknown, taken near Valparaiso, 
Chile, U.S. Naval Expedition (no other data). 

Distribution.— Pacific Coast of Chile between about 27°S and 42°S (Caldera to 
Puerto Montt). Plate (1896) stated, "Coquimbo southward to Tierra del Fuego." 

Z)/'^^/705/.9. — External gill apertures and gill pouches 10(11). Last gill aperture, left 
side, closely adjacent to, but separate from, pharyngocutaneous duct. Prebranchial and 
tail lengths each greater than branchial length. Body robust throughout. Ventral finfold 
absent or very weakly developed. Color purplish-black, with pale areas and spots, 
principally at mouth and on ventral surface anterior to gill apertures. Spots sparsely 
scattered over body. 

Description. —Counls (Tables 1-3) and measurements (Table 4) are provided and 
compared with similar data for E. polytrema and E. nanii. 

Body robust throughout; greatest width 67% (52-82%) of greatest depth, increas- 
ingly laterally compressed toward tail. Prebranchial and tail lengths each greater than 
branchial length. Depth at cloaca 71% (61-128%) of greatest body depth. Tail slender, 
spatulate, the ventral outline nearly straight, slanting slightly downward from cloaca, 
its length about 17% (14-22%) of TL, its depth 42% (35-52%) of its length. Ventral 
finfold usually absent but a very low one occasionally present. Caudal finfold moderately 
thickened throughout, ending dorsally over cloaca. 

Head at eyespots slightly deeper than wide. Nasopharyngeal aperture about one- 
third to one-fourth of width of head at eyespots. Eyespots small but prominent, the 
margins sharply defined. Face sloping at a very slight angle from rostrum. First two 
pairs of barbels about equal in length, the first 97% (66-131%) of length of second pair 
and 76% (48-100%) of the third, the second 77% (55-100%) of the third. 

Color a very dark brown to purplish-black with randomly scattered small pale 
spots extending to about cloaca; none were observed in the tail area. The spots are 
concentrated in the branchial area and are particularly prominent near the mouth. 
Distal portions of barbels with pale tips. GA and slime pores without pale margins. 

Head grooves present near eyespots with a greater number before than behind in 
contrast to the arrangements in E. polytrema and E. nanii. The number of grooves in 
each series is variable, ranging between one and four. 

All GA are very small, much smaller than in E. polytrema and E. nanii. In all our 
material, the efferent duct of the last GP, left side, is not confluent with that of PCD 
but lies closely adjacent; the GA is an elongate slit lying very close to PCD and may 
easily be overlooked. 

DM long, robust, 29% (25-36%) of TL, its width 13% (10-19%) of its length, its 
depth 71% (46-80%) of its width. VA very short, 9% (8-1 1%) of length of DM, branching 
only slightly anterior to the ventricle. No ABA lead to GP from VA (Fig. 3C). From 
to 4 GP may lie between VA and DM, the remainder lying anterior to tip of DM, 
the latter often overlying VA (Fig. 3C). This arrangement is very similar to that of E. 
cirrhatus (McMillan and Wisner, 1984, fig. 3). 

Eggs.—OfXhc females examined, only three have well developed eggs. One, 590 
mm TL (SI072-149), has 40 eggs ranging between 20 mm by 5.8 mm and 23 mm by 
6.5 mm. Another, 480 mm TL (SI072-148), has 12 eggs between 23 by 6.8 mm and 
25 by 7.7 mm. A third, 485 mm TL (SIO81-102), has 10 eggs between 15 by 4.7 mm 
and 17.5 by 5.3 mm. It is not known if the two bearing few developed eggs contain 
the original number, but there is no indication of damage that could have caused loss 
of eggs. All three ovaries contain many tiny, round eggs, plus a few in early stages of 
elongation, about 3 by 0.8 mm. No eggs have protruding anchor filaments, although 
polar caps are well developed on many. 



238 



Eptatretus polytrema (Girard 1854) 

Bdellostoma polytrema Girard 1854:199 (original description; 15 gill openings; Valparaiso Bay, 
Chile), 1855:252-253, pi. 23, fig. 1, 1855b:48-49 (relation to Gastrobranche dombeyi of 
Lacepede); description; 1 4 gill openings and gills; color not preserved in specimen described); 
Giinther 1870:512 {Gastrobranche dombeyi of Lacepede doubtfully synonymized; Girard's 
count of 14 gill openings doubted, may have included mucus pores; coast of Chile); Schneider 
1880:115-116 (note on status; no locality given; 1 4 gill openings; description, after Gunther); 
Porter 1903:193, 233 (14 gill openings, each side); Quijada 1913:128 (14 gill openings, each 
side; coast of Chile); Rauther 1924:685 (14 gill openings, each side; coast of Chile); Adam 
and Strahan 1 963:5 ( 1 4 pairs of gills, variation unknown; average length 450 mm, maximum 
570 mm; Chile). 

Homea polytrema. Dean 1903:295-298, fig. 3 (in part; figure of a piebald specimen showing 14 
gill openings; Valparaiso, Chile). 

Heptatretus polytrema. Regan 1912:534-535 (14 gill openings; Valparaiso, Chile). 

Polistotrema polytrema. Fowler 1951:267 (14 gill openings; Chile); Buzeta 1964:49, 51 (13 to 14 
gill openings; color slate gray with white spots over body, bordering on dappled aspect; 
Valparaiso to Talcahuano, Chile). 

Eptatretus polytrema. Johansen and Strahan 1963:352-353 (14 pairs of gills). 

Neotype.—SIOM-IA?,, female, 431 mm, TL; taken off Valparaiso, Chile, at 350 
m; no other data; received as a gift from Dr. Alberto Nani, University of Chile, Viiia 
del Mar, November 1970. 

Additional material examined.— S1065-613, male, 429 mm TL, and female, 397 
mm TL, taken in Valparaiso Harbor, Chile, in a trap on bottom at 30 m, 23-24 
December 1965; SI072-148, two females, 371-440 mm TL, taken in Bahia Inglesa, 
27°07'S, 70°55'W, in a trap on bottom at 20 m, 9-10 April 1972; SI08 1-103, female, 
460 mm TL, taken off Valparaiso, Chile (no other data); USNM 272582, two females, 
400-430 mm TL, taken at 33°32'S, 7r52'W, in a 72 ft shrimp trawl between 260 and 
270 m, 1 August 1966; CAS 56511, three females, 385-447 mm TL, one male, 420 
mm TL, taken at 33°22'S, 71°53'W, in a 72 ft shrimp trawl between 240 and 260 m, 
1 August 1966; LACM 43775-1, female, 410 mm TL, taken at 33°27'S, 77°52'W, in a 
72 ft shrimp trawl between 175 and 180 m, 1 August 1966; MNHNC (S) P. 6379, 
male, 395 mm TL, taken at 29°37.5'S, 71°21'W, in a 72 ft shrimp trawl at 1 10 m, 14 
August 1966; MNHNC (S) P. 6380, male, 440 mm TL, taken in area of Talcahuano- 
Concepcion, Chile, in a shrimp trawl (depth not recorded), 8 August 1972. 

Distribution.— Bahia Inglesa to Concepcion Chile. All specimens examined were 
taken between 10 and 350 m. On two occasions, E. polytrema was taken with E. 
bischoffii in Valparaiso Harbor in traps at 30 m and once in Bahia Inglesa (27°07'S, 
70°55'W) in a trap at 20 m. Also, it was taken once with E. nanii at 33°22'S, 7r52'W 
in a 72 ft shrimp trawl between 260 and 270 m. 

Diagnosis. — External gill apertures 14-14; gill pouches 13-14. The neotype has 12 
gill apertures on the left side (excluding the PCD), 13 on the right, and 13-13 gill 
pouches. Branchial length greater than prebranchial or tail lengths. Three fused cusps 
(multicusps) on both the anterior and posterior sets of cusps. Body moderately slender. 
Color piebald, with pale areas varying in size and numbers, randomly scattered over 
a dark background (Fig. 4). Ventral finfold varies between absent to well developed. 
Head grooves present near eyespots. Efferent duct of last GP, left side, confluent with 
that of PCD in 39% of specimens (7 of 18). VA short, 14% (3-23%) of length of DM. 

Description.— Counis (Tables 1-3) and morphometries (Table 4) are given and 
compared with similar data for E. nanii and E. bischoffii. Body moderately slender, 
increasingly laterally compressed toward tail, deepest at about midlength; greatest body 
width about 70% of greatest depth; depth at cloaca 70% of greatest body depth. Ventral 
finfold variably developed, ranging from absent to prominent; it is absent in the neotype. 
Of the 19 specimens, 12 (385-470 mm TL) have no or only vestigial ventral finfolds; 
two (390-420 mm TL) have slight but distinct ones, and three (289-440 mm TL) have 
well developed ones. Apparently size is not a factor in development of ventral finfolds. 
Tail spatulate, its ventral outline nearly straight, slanting moderately downward from 



239 



cloaca; its length 15% (13-18%) of TL, its depth 44% (43-45%) of its length. Caudal 
finfold moderately thin, extending a short distance out from musculature. Ventrally it 
is thick with no extension of tissue, but expands around tip of tail and continues dorsally 
to about over cloaca, becoming thicker anteriorly. Color highly variable, with few to 
many pale blotches against a dark background. Extreme variation in the piebald con- 
dition is shown in Figure 4; the two specimens were taken together (SI072-148). 

Head at eyespots about as deep as wide, narrowing to rostrum. Nasopharyngeal 
aperture small, its width one-fourth of head width at eyespots. Face sloping 1 5 to 30 
degrees from the horizontal. First two pairs of barbels nearly equal in length, the first 
pair often slightly shorter, each about two-thirds the length of third pair. All barbels 
white-tipped on distal third to half. Eyespots prominent, the margins well defined. 

Head grooves present on all specimens in good condition, usually behind the 
eyespots on each side of dorsal midline. About one-fourth, including the neotype, also 
have grooves before the eyespots arranged longitudinally. There are one to six grooves 
behind, and one to four before, the eyespots. 

Length of DM 26% (23-30%) of TL. DM width 13% (11-16%) of its length, its 
depth 65% (49-74%) of its width. VA short, 14% (3-23%) of length of DM. An average 
of 2.25 (1-4) GP lie between ventricle and branching of VA, 2.28 (0-6) lie between 
branching and DM, and 8 (5-10) GP lie anterior to tip of DM (Fig. 3A). In general, 
the branchial slime pores lie below the level of, and about midway between, the 
adjacent GA. 

Eggs.— A female, 422 MM TL (SI065-676), has 40 well developed eggs, all 17 to 
19 mm in length and about 7 mm in diameter. Of the 19 specimens, 13 are mature 
females with developing eggs; one immature (289 mm TL) has eggs in the round 
undeveloped stage. Two specimens (CAS 56511) have large eggs; a 447 mm TL female 
has 32, the largest 16 mm by 4.5 mm; one well developed egg measures 8 mm by 2.5 
mm. A 385 mm TL female has 24 well developed eggs, the largest 27.5 by 7 mm, the 
smallest 23 by 6.5 mm. A 431 mm TL female has 40 eggs, about 17 by 6 mm. A series 
of developing eggs is present in three females and range in size from 0.5 to 6.0 mm; 
most are nearly round (1.0 to 1.5 mm in diameter). 

Discussion o/"Eptatretus polytrema.— Girard (1854:199, and 1855:252-253, pi. 3, 
figs. l-5b) based Bdellostoma polytrema on a specimen described as having "Fourteen 
respiratory apertures and gills on either side." He further stated "Color not preserved 
in the specimen described." and, "in a precarious state of keeping." 

On February 25, 1975, at the U.S. National Museum, the late Carl L. Hubbs 
examined a specimen (USNM 78530), about 440 mm TL, labeled as type oi Bdellostoma 
polytrema (by J. O. Snyder), taken near Valparaiso, Chile, by the U.S. Naval Astro- 
nomical Expedition. Hubbs' notes state, "It is in bad shape, but body is largely intact. 
Most of the skin has sloughed off. Gill pouches still discernible, 10 left and 1 1 right, 
with the last one on the right less than half the bulk of others [the specimen had not 
been opened prior to Hubbs' examination]. The skin was dark, but probably not black, 
and nowhere is there a trace of light areas. The main blood vessel [ventral aorta] 
branches opposite the anteriormost [sic; obvious misstatement for posterior] gill pouch- 
es of each side. Only 3 gill pouches, each side, lie behind [posterior to] the end of the 
huge tongue muscle. Slime pore counting seems to be impossible." 

However, Girard's original (1854) description, although brief, unequivocally stat- 
ed, "14 respiratory apertures and gills on either side," and this is reiterated in his 
subsequent (Girard 1855) account and figure of what must be the same specimen. The 
question then arises, how did a specimen with 10 gill openings come to be labeled as 
the type? We have asked G. David Johnson (USNM) to examine the putative holotype 
for us. He reports that Hubbs' description of it is accurate; i.e., there are 10 gill openings. 
However, there is a label in the bottle that reads, "Valparaiso, United States Exploring 
Expedition." This is the Wilkes Expedition of 1838-42, and Girard's specimen was 
collected during the U.S. Naval Astronomical Expedition to Chile of 1849-52. We can 
only speculate, but it seems possible that Girard's specimen, which he stated was in 
poor condition, was discarded or lost and that subsequently another specimen from 
Valparaiso was mistakenly regarded as the holotype of B. polytrema and so labeled. 



240 

We follow Girard in using the name polytrema for a species of Eptatretus with 1 4 
gill apertures. No specimen conforming to Girard's description and bearing appropriate 
data is in either the National Museum of Natural History or the Academy of Natural 
Sciences of Philadelphia, and therefore, the holotype of Bdellostoma polytrema Girard 
must be presumed lost. 

In order to stabilize usage of the name we have above selected a specimen (SI084- 
243) as neotype. For full data see Material Examined. 

Unassignable Records 

Early in an attempt to revise the Myxinidae, the late Carl L. Hubbs constructed a 
lengthy synonymy of what was then thought to be Eptatretus polytrema (Girard 1854). 
Hubbs was aided in the compilation of citations in the Spanish language by Gumersindo 
Revuelta A., then a student of Alberto Nani C. at the University of Chile, Viiia del 
Mar. We have determined that a majority of the citations pertain to no recognizeable 
species in that neither counts, useful proportions, nor color notes were provided. As 
the three species discussed here are sympatric throughout much of their ranges, such 
references are not useful in distinguishing between them. Thus, we have extracted those 
citations that definitely pertain to E. bischoffii and E. polytrema, by reason of data 
provided by authors. Unfortunately, we are unable to assign any definite references to 
E. nanii. 

We list below those references that provide no clue as to species but have been 
placed in the synonymy of E. polytrema by various authors. 

Gastrobranche Dombey Lacepede 1798:41 4-4 1 5 (original description, based on a dried 
skin brought to Paris by a traveler, Dombey; apparently a myxinid but genus and 
species indeterminate; nomen dubium), 1799:990-992, pi. 23, fig. 1 (German 
language version of original description; nomen dubium) [The dried skin is not 
now in the collection of the Paris Museum, personal communication, M. L. Bauch- 
ot.] 

Gastrobranchus Dombeyi. Shaw 1804:267-268 (after Lacepede); Fleming 1822:375 
{Gastrobranchus Dombay of Lacepede is probably of the genus Homea); Girard 
1855a:251 (relation to Bdellostoma polytrema). 

Bdellostoma Dombeyi. Miiller 1834:80 (based on Gastrobranche Dombeyi Lac; no gill 
openings stated; doubtful whether a Bdellostoma or Myxine)\ Schneider 1880:1 15 
(notes on status); Jordan and Gilbert 1883:57 (in part; attributed to Miiller; range 
to southward); Gastrobranche Dombev Lac, Miiller 1834, and B. polytrema Girard 
synonymized); Diicker 1924:507-514, 524-526, pi. 27, figs. 16, 18, pi. 28, figs. 
19-25 (eye structure in detail; Coquimbo, Chile); Holmberg 1970:519-520, 536- 
537 (eye degenerate; after Diicker 1924). 

Bdellostoma polytrema. Philippi 1857:266 (cited); Lockington 1878:793 (B. stoutii 
compared; Chile); Gunther 1880:25 (cited), 82 (hsted); Jordan and Gilbert 1883: 
6 (cited); Reed 1897(2:671 (catalogue; coast of Chile, Valparaiso), 1897Z):22 (cat- 
alog); Delfin 1 899: 1 78 (listed), 1 900a: 1 86 (listed; Talcahuano to Valparaiso, Chile), 
1 900^7:422 (voraciousness; fishes more or less consumed from within); Porter 1 900; 
Gill 1901:737 (£■. Dombeii of Cloquet [1819] a composite description drawn from 
two authors and representing two species); Reed 1901:23 (listed); Wolnitzky 1901: 
56 ("black congrio"; coast fishery, Anconcagua [possibly an Ophidiid]); Quijada 
1912:109 (Coquimbo and Valparaiso, Chile); Lahille 1915:370 (cited); Rauther 
1924:685 (brief description); Ohver Schneider 1936:99 (cited); Guerrero 1939: 
10-11 (cited; PI. 1); Tortonese 1942:228 (cited); Henckel 1944:69 (description of 
eyes); Lama 1944; Lindberg and Legeza 1959:22, and 1967:19 (reference; not in 
Japan). 

Hetpatretus dombeyi. Jordan and Gilbert 1 883:867 (identity of Polistotrema stouti with 
H. dombeyi doubtful; Chile). 

Polistotrema dombey (or dombeyi). Jordan and Evermann 1896:6 (brief description); 
Porter 1909:52, 53 (synonymies), 1910:73, 74 (listed; synonymies); Lahille 1915: 



241 



350, 370 (listed); Oliver Schneider 1943^:76 (habits; distribution), 1943/?:6, 49 
(listed); Holmberg 1970:519-520, 536-537 (compared in eye structure with Mva7>2<? 
glutinosa on basis of Diicker 1924). 

Homea polytrema. Garman 1899:344 (compared with MvJC/>2^c/>c//ro/?5); Delfin 1902^2: 
186 (listed), 1 902/7:2 1 9 (voraciousness); 1 903: 1 82 (cited; reference to 1 902/)); Dean 
1904:20 (synonymy; characters; coast of Chile); Albert 1914:82, 85, 89, 91, 93 
(listed); OUver Schneider 1936:99 (cited); Henriquez 1957:1 (cited). 

Polistostrema polytrema. Fowler 1908:461 (listed); 1941:3 (listed, synonymies); Mann 
1954:18 (key), 84, 90 (cited), 91, 92 (brief description); Yaiiez 1955:41 (cited), 42 
(fig. 4); deBuen 1957:266 (listed), 1959:35 (listed); Pequefio 1968:6 (listed); Ba- 
hamonde and Pequefio 1975:5 (listed); Pequeno and Lopez 1979 (not seen). 

Polistotrema decatrema. Fowler 1941:4 (listed, synonymies). 

Dodecatrema polytrema. Fowler 1947:1 1 or more gill openings on each side of body; 
3 (Type Bdellostoma polytrema Girard; Polistotrema synonymous with Homea; 
synonymies). 

Homea decatrema. Fowler 1951:267 (gill openings 6 [error?, possibly Eptatretus laura- 
hubbsaesee key]); Mann 1954:18 (key); deBuen 1957:266 (Hsted). 

Bdellostoma (Polistotrema) decatrema. Tortonese 1951:86 (San Vincente, Chile [Val- 
paraiso Harbor]). 

Eptatretus polytrema. Femholm 1975:203 {Bdellostoma bischoffli Schntid&v synonym: 
anchor filaments on egg widespread); Femholm and Holmberg 1975:253, 255- 
256 (reference to Diicker 1924, on eyes, as Bdellostoma dombey). 



Phylogenetic Relationships 

It is not now feasible to attempt construction of a meaningful phylogeny for species 
(about 1 5) o{ Eptatretus. A fossil record is non-existent for the group, body proportions, 
with few exceptions, are quite similar, and color is highly variable, often within species. 
As discussed already, the number of gill openings (apertures) and associated internal 
gill pouches offer the only readily available means of grouping the species o^ Eptatretus. 
Based on these gill characters, three species groups can be recognized: one having 5 or 
6 GA; a second having 7 GA only; and a third having 8 to 1 5 GA. Whether or not 
this grouping has any phylogenetic significance is a question for future investigations. 



Acknowledgements 

We are most grateful to the late Dr. Carl L. Hubbs for initiating a review of the 
Myxinidae of the world. Without his early efforts to accumulate a large amount of 
material and data, we would never have accomplished this study. Also, we are deeply 
grateful to, and sincerely thank the following Chilean scientists for invaluable aid: Dr. 
Alberto Nani Caputo and his student Gumersindo Revuelta Alfaro, formerly of Uni- 
versity of Chile, Viiia del Mar, gave particular aid in providing specimens, literature 
citations, and information on distribution. Dr. German Pequeiio, University of Chile, 
Valdivia, and Dr. Roberto Melendez, National Museum of Natural History, Santiago, 
kindly provided specimens. G. David Johnson, Associate Curator of Fishes, National 
Museum of Natural History, kindly provided data on specimens taken by the AL- 
BATROSS off Southern Chile and examined the putative type of B. polytrema. 

In particular, we thank Leslie W. Knapp (R/V ANTON BRUUN, Cruise 18, 
Richard S. Lee, Ronald McConnaughey, and Charles F. Phleger (Expedition South 
Tow, R/V THOMAS WASHINGTON) for their efforts in collecting specimens. Richard 
H. Rosenblatt critically read the manuscript and offered valuable suggestions. Maria 
Vernet kindly provided the Spanish language version of the Abstract. 

Two biological oceanographic expeditions provided a major share of the study 
material: Cruises 1 2 and 1 8a by R/V ANTON BRUUN, Southeastern Pacific Biological 
Oceanographic Program, sponsored primarily by the National Science Foundation, and 



242 



Expedition South Tow (Legs 3 and 4) by the Scripps Institution of Oceanography, 
sponsored in part by the National Science Foundation and Office of Naval Research. 
We are indebted to these sponsoring agencies for financial support, and to the many 
persons aboard the vessels for their time and eifort toward the collection of specimens. 



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MCZ 
LIBRARY TRANSACTIONS 

OF THE SAN DIEGO 

MAR 7 1988 natural history 

HARVARD 
UNIVERSITY 

Volume 21 Number 15 pp. 245-257 24 February 1988 

Two crabs, Xandaros sternbergi (Rathbun 1926) n. gen., and 

Icriocarcinus xestos n. gen., n. sp., from the late Cretaceous 

of San Diego County, California, USA, and Baja California Norte, Mexico 

Gale A. Bishop 

Institute of Arthropodology and Parasitology. Department of Geology and Geography, 
Georgia Southern College, Statesboro, Georgia 30460-S149 

Abstract. Two collections containing 14 specimens of late Cretaceous crabs from Carlsbad, San 
Diego County, California, and Punta San Jose, Baja California Norte, Mexico, yield new data on Pacific 
Slope Cretaceous decapods. Three specimens of Cretaceous decapods from Punta San Jose are preserved 
in calcareous concretions from the Rosario Formation and eleven specimens associated with a diverse 
molluscan fauna from Carlsbad are preserved in sandy claystone of the Point Loma Formation. Three 
crabs from Punta San Jose and six specimens from Carlsbad are assigned to Xandaros sternbergi 
(Rathbun 1926), n. gen. Five specimens from Carlsbad are assigned to Icriocarcinus xestos, n. gen., n. 
sp. Xandaros sternbergi is a xanthid crab with a massive body and massive, spatulate chelae. Icrio- 
carcinus .xestos is a carcineretid crab with a wide, flattened carapace and heterochelous, keeled claws. 
One specimen of /. .xestos is preserved in a simple oblique burrow. 

Introduction 

Previous u'orA:. — The Cretaceous record of Pacific Slope crabs is sparse (Bishop 
1986/?) consisting of rare specimens of six described species. Woodward (1896) de- 
scribed the crabs Plagiolophus Vancouver ensis, Homolopsis richardsoni, and Palaeo- 
corystes harveyi from British Columbia. Rathbun (1908) described Archaeopus anten- 
nuatus from San Mateo County, California, and later (Rathbun 1 926) described a unique 
cheliped from, "5 miles north of Carlsbad Station, Santa Fe Railway, San Diego County," 
as Zanthopsis sternbergi with the remark: "While this cheliped has the general form of 
a Zanthopsis, it differs from all other species of which the cheliped is known by the 
greater number and different disposition of tubercles." In 1929, Glaessner reassigned 
Plagiolophus vancouverensis to Archaeopus and Palaeocorystes harveyi to Notopocor- 
ystes. 

Richards (1975) described Longusorbis cuniculosis from the Spray Formation (late 
Campanian or early Maastrichtian) on Vancouver Island. The exquisite preservation 
of 83 specimens was ascribed to their being buried and fossilized in their burrows. One 
nearly complete burrow is figured (Richards 1975, fig. 6) and is differentiated from the 
substrate in which it was constructed by the texture and color of the burrow fill. 

Feldmann and McPherson (1980) reviewed the fossil decapod crustaceans of Can- 
ada attempting to bring that scattered literature together into a revisionary paper. This 
attempt was successfully completed for the lobsters but was only partly complete for 
the crabs. 

Bishop (1983) erected Zygastrocarcinus and reassigned Homolopsis richardsoni to 
Zygastrocarcinus. Sundberg and Riney (1984) published a preliminary report on the 
invertebrate fauna from the Point Loma Formation collected near Carlsbad, California, 
including an illustration of an indeterminate decapod (Sundberg and Rinev 1984:105, 
fig. 3.9). 

The collections. —A collection of fossil crabs was made by Mr. Edward Hennessey 



246 





retaceous 
utcrop 



MEXICO 



ENSENEDA 



Punta San Jose 

2 




Punta San Jose 



Figure 1. Geographic location of collection sites near Carlsbad (1), and Punta San Jose, Baja California 
Norte (2). 

of Long Beach, California, from the upper Cretaceous Rosario Formation as exposed 
in the sea cUffs at Punta San Jose, Baja California Norte (Figure 1.2). Three specimens 
in this collection are preserved in ovoid, calcareous concretions with portions of the 
crabs exposed at the concretion surfaces. Varying portions of the carapace are exposed 
giving rise to a "pseudomorphology" that could easily confuse the casual observer and 
lead to false conclusions about its actual morphology. 

A second collection consists of 1 1 specimens collected by Bradford Riney and 
Thomas Demere, Department of Paleontology, San Diego Natural History Museum 
from the Point Loma Formation, Carlsbad, CaHfomia (SDSNH Loc. 3162, Figure 1.1). 
The Cretaceous section here is considered to be late Campanian or early Maastrichtian 
in age (Sundberg and Riney 1984). Specimens of two species are preserved as clay- 
filled exoskeletons or as exfoliated clay steinkems. The specimens received for study 
had been prepared from the surrounding claystone with a pin vise. Preparation with a 
needle and pin vise in Statesboro further freed several specimens from the enclosing 
matrix. One specimen was preserved in situ in its shell-filled burrow. Sundberg and 
Riney (1984) considered the Carlsbad invertebrate fauna to have inhabited a firm mud 
bottom below wave base. This diverse fauna is characterized by Indogrammatodonl 
sp., Crassatella sp., Limopsis sp., Tellinidae indet., Calva sp., Syncydonema sp., Den- 
talium sp., Anchura sp., Gyrodes sp., and Volutoderma sp. The six crabs are preserved 
in claystone, as articulated specimens commonly with the exoskeleton intact. The 
preservation is so fine that setal pits are preserved, as are patterns attributable to color 
markings. 

Abbreviations used in the text include SDSNH, San Diego Natural History Mu- 
seum, Department of Paleontology; EH, Edward Hennessey, private collection; and 
USNM, United States National Museum, Smithsonian Institution. 



247 



Systematic Paleontology 

Order Decapoda Latreille, 1 803 

Infraorder Brachyura Latreille, 1803 

Section Branchyrhyncha Borradaile, 1907 

Superfamily Portunoidea Rafinesque, 1815 

Family Carcineretidae Beurlen, 1930 

Icriocarcinus, new genus 

Type species.— Icriocarcinus xestos, new species. 

Z)/a^A705/5.— Carapace pentagonal, twice as wide as long, well differentiated by 
grooves into smooth, plateau-like areolations. Rostrum very narrow, downtumed, not 
grooved, rounded at tip. Anterolateral margin with two small orbital spines plus large 
spine at widest point Vy distance from front. Orbits large, eyestalk long and slender. 
Posterolateral margins straight and steep. Posterior margin slightly concave. Areolations 
on carapace raised into plateaus, small transverse ridge on protogastric region even 
with distal ends of cervical groove. Anterior portion of epibranchial lobe developed as 
a narrow, distal ridge behind cervical groove. Cardiac region bilobed, decreasing in 
relief posteriorly until merging with intestinal region. Chelipeds long, arched upward, 
keeled and slightly heterochelous. Walking legs long, P. oval, P3-P5 flattened, P5 smallest 
with straight dactylus. 

Etymology. —The generic name Icriocarcinus is compounded from the Greek words 
"Ikrion," scaffold, bench, or platform, and "Karkinos," crab; or "platform crab." 

Comparison.— T\iQ carapace shape, long and slender eyestalks, areolation, trans- 
verse ridging, and heterochely typical of the Carcineretidae are well exhibited by this 
species. The Carcineretidae seems to consist of two natural groups, one with straight, 
lobed fronts, bilobed rostra, and a similar U-shaped carapace {Ophthalmoplax Rathbun 
1935; Woodbinax Stenzel 1953; and Carcineretes Withers 1922) and another with 
pentagonal or subhexagonal carapaces, spiny or lobed fronts, narrow non-bifurcated 
rostra, and somewhat similar carapace areolation including more or less developed 
transverse ridges {Cancrixantho Van Straelen 1934; Longusorbis Richards 1975; Icrio- 
carcinus new genus; and probably Lithophylax A. Milne Edwards and Brocchi 1879). 

Icriocarcinus differs from the first group {Ophthalmoplax, Woodbinax, and Car- 
cineretes) by its pentagonal shape, slanted anterolateral margins, and areolation. Icrio- 
carcinus is similar to members of the second group {Cancrixantho, Longusorbis, and 
Lithophylax) in carapace shape, areolation, possession of a narrow rostrum, and trans- 
verse ridging of the carapace. Icriocarcinus differs from Lithophylax by being much 
larger, less arched, and by lacking a posterior transverse ridge on the cardiac and 
mesobranchial regions. Icriocarcinus differs from Cancrixantho by being proportionally 
wider; having oblique anterolateral margins; having smaller, better defined anterolateral 
spines; having its widest point more posterior; lacking the posterior transverse ridge 
on the epigastric and mesogastric regions; and lacking the three pronounced postero- 
lateral spines oi Cancrixantho. Icriocarcinus is most similar to Longusorbis from which 
it differs by being proportionally wider; having a concave front; a narrower, non-grooved 
rostrum; having its widest part more posterior; having a less distinctly concave posterior 
margin; having flat, rather than tumid, tuberculate areolations; having one anterior 
transverse ridge across the protogastric regions on line with the distal part of the cervical 
furrow; and having more elongate, upwardly arched, more keeled chelae than Lon- 
gusorbis. 

Icriocarcinus xestos, new species 
Figures 2; 3A-D 

Types. -WoXoXy^t (SDSNH 26038) and paratypes (26040, 26101, 26113, 26202) 
are deposited in the Paleontology collections of the San Diego Natural History Museum. 

Occurrence, sample size, and preservation.— ¥'\\e specimens were collected from 
the Point Loma Formation at the Carlsbad Research Center (SDSNH Loc. 3162) and 
are late Campanian or early Maastrichtian in age. The holotype (SDSNH 26038) is a 



248 




Figure 2. Icriocarcimis xeslos. n. sp. A, holotype, SDSNH 26038. dorsal view of carapace and appendages; 
B-D, paratype, SDSNH 26202; B, ventral view of sternum, abdomen, and appendages; C, outer face of right 
claw; D, outer face of left claw. Bar scales = 1 cm. 



249 




Figure 3. A-D, Icriocarcimis xestos, n. sp. A, paratype, SDSNH 261 13, dorsal view showing anterolateral 
marginal spines on carapace and spine rows on upper surface of left claw; B, paratype, SDSNH 26 10 1 , ventral 
view; C, holotype, SDSNH 26038, outer face of left claw; D, paratype, SDSNH 26040, specimen preserved 
at bottom of burrow with claws exposed, burrow in claystone filled with sand and shell fragments. E-H, 
Xandaros sternbergi (Rathbun 1926), E-F, topotype, SDSNH 26036, carapace and venter; G, topotype, 
SDSNH 26037, carapace, both chelipeds and pereiopods; H, hypotype, EH-1, carapace in concretion showing 
lateral wing. Bar scales = 1 cm. 



250 



Table 1 . Measurements (mm) of Icriocarcinus xestos, n. sp. 







Holotype 


Paratype 1 


Paratype 2 


Paratype 3 


Paratype 4 






SDSNH 


SDSNH 


SDSNH 


SDSNH 


SDSNH 






26038 


26101 


26202 


26113 


26040 


Carapace 














Length 




19.62 


— 


— 


20.5 


— 


Width 




37.13 


— 


— 


36.1 + 


— 


Height 




— 


— 


— 


— 


— 


Orbital Width 


(17±) 


— 


— 


18.8± 


— 


Rostral Width 


— 


— 


— 


1.1 


— 


Abdomen 














A, 


length 


— 


— 


1.0? 


— 


— 




width 


— 


— 


— 


— 


— 


A. 


length 


— 


— 


1.0± 


— 


— 




width 


— 


— 


— 


— 


— 


A3 


length 


— 


— 


1.1 


— 


— 




width 


— 


— 


— 


— 


— 


A4 


length 


— 


— 


1.5 


— 


— 




width 


— 


— 


6.9 


— 


— 


As 


length 


— 


— 


1.3 


— 


— 




width 


— 


— 


— 


— 


— 


Ae 


length 


— 


2.5 


4.5 


— 


— 




width 


— 


4.5 + 


— 


— 


— 


T 


length 


— 


2.3 


2.5 


— 


— 




width 


— 


3.7 


5.0 


— 


— 


Chelipeds 




Left/Right 


Left/Right 


Left/Right 


Left/Right 


Left/Right 


Coxa 


length 


— /— 


4.0/- 


2.4/- 


—/— 


—/— 




width 


— /— 


— /— 


— /— 


— /— 


—/— 


b/i 


length 


— / — 


5.1/- 


4.5/- 


— / — 


— / — 




width 


— / — 


— / — 


— / — 


— / — 


— / — 


Merus 


length 


— / — 


12.5+/- 


14.3+/- 


— / — 


— / — 




width 


— /— 


— /— 


— / — 


— / — 


— / — 


Carpus 


length 


9.1/- 


—/— 


— /— 


— /— 


— /— 




width 


— /— 


—/— 


—/— 


—/— 


—/— 


Propodu; 


; length 


24.0/- 


22.6+/18.3 + 


28.7/33.3 


22.5/26.8 


31.5/34.4 




width 


— / — 


-/5.3 


-/7.3± 


— / — 


7.8/8.7 


Dactylus 


length 


—/— 


— /— 


-/14.6 


-/10.5 


-/15.4 




width 


—/— 


— /— 


—/— 


—/— 


— /— 



nearly complete steinkem (Figures 2A, 3C); paratype 2 (SDSNH 26202) preserves the 
carapace, chelipeds, rostrum and anterolateral spines (Figure 2B-D); paratype 1 (SDSNH 
26101, Figure 3B) and paratype 3 (SDSNH 261 13, Figure 3 A) preserve sterna, abdo- 
mens, and pereiopods; paratype 4 (SDSNH 26040) is preserved in a shell-hash-filled 
burrow (Figure 3D). This burrow is oriented oblique to bedding and measures 3.0 to 
4.8 cm in diameter and at least 14 cm in length. The fragile, thin exoskeleton was 
probably preserved on each specimen but exfoliated very rapidly due to mechanical 
abrasion and humidity changes on all the specimens except paratype 2 (SDSNH 26202). 

Diagnosis. — Same as for the genus. 

Etymology.— The. trivial name is derived from the Greek word "xestos," scraped, 
planed, or smoothed relating to the smooth plateau-like areolations on the carapace. 

Description. —Carapace pentagonal, ovoid, twice as broad as long (Table 1), slightly 
arched transversely, arched longitudinally, somewhat depressed in center, well differ- 
entiated by grooves. Carapace front broad, sinuous. Rostrum narrow, downtumed, 
ungrooved giving way laterally to broad orbital regions (50% of carapace width). An- 
terolateral margins broadly rounded with three spines, one at outer angle of orbit?, one 
at midpoint, and the largest forming anterolateral comer and widest part of carapace 
'/3 distance from front. Posterolateral margins straight, sharply reflexed into a near 
vertical surface; posterolateral angle rounded; posterior margin slightly raised into rim 



251 



and concave. Carapace grooves narrow, separating well delineated, plateau-like areola- 
tions. Cephalic arch well differentiated; gastric region well differentiated, depressed 
somewhat at center; mesogastric broadly ovoid, rounding rapidly onto very narrow 
anterior tongue terminating before reaching rostrum. Protogastric lobes divided by a 
distinct transverse line of flexure, forming a ridge near posterior '/3 (on line with cervical 
groove) of the mesogastric region. Urogastric region transverse, convex posteriorly. 
Hepatic regions transversely wide, longitudinally narrow, forming anterolateral margin 
of carapace with its three marginal spines. Scapular arch moderately differentiated, 
especially medially. Cardiac region raised into a bilobed level plateau anteriorly, 
gradually decreasing in relief posteriorly, merging indistinguishably into the intestinal 
region. Branchial regions differentiated into well-delimited epibranchial regions and 
posterior meso-metabranchial regions which are broadly swollen with three short mar- 
ginal ridges; one near front, the second at midpoint, and the third near posterolateral 
angle. These ridges arise as small tubercles on the lateral margin of the edge of the 
dorsal shield, become raised and transverse before becoming obsolete. Anterior edge 
of epibranchial subdivided distally by a small, subparallel auxiliary groove posterior 
to the cervical groove giving rise to a distinctive, short, distal, transverse anterior 
epibranchial ridge. Two subparallel lines of muscle insertions are present, one posterior 
to distal cervical groove and one subparallel to groove between epibranchial and me- 
sobranchial. [The terms cephalic arch and scapular arch as used herein follow the 
terminology of H. Milne Edwards (1834-40) and Bell (1858). These authors distin- 
guished the anterior portion of the carapace (cepahlic arch) consisting of the frontal, 
orbital, gastric, and hepatic regions from the posterior portion (scapular arch) formed 
by the branchial and cardiac regions.] 

Carapace evenly covered by dense, fine granulation arranged in patterns of lines 
forming swirls. Exoskeleton exceedingly thin over the entire crab. Sternum transversely 
ovoid, relatively flat. Anterior somites fused (1-4) with slight transverse flexure, divided 
into anterior shelf and posterior sternal "plane" at same level as other somites; somites 
5-7 wedge-shaped, widest distally; posterior portion of somite 5 forms widest part of 
sternum; somite 6 narrower than 5 but with longer distal edge; somite 7 narrower than 
6 and shorter; somite 8 barely visible beneath abdominal flap. Abdomen with at least 
six segments, the penultimate being longest and those proximal being about the same 
size and much shorter than either of last two segments; last three segments on males 
about same width ('/3 of sternal width), the more proximal are wider (% of sternal width 
and very narrow). Eyestalk long and slim, apparently folding back into long orbit 
extending beneath front from rostrum to first anterolateral spine. Maxillipeds spatulate, 
endognath slightly narrower than exognath, perhaps twice as long as wide; endognath 
serrate on medial edge; proximal end of endognath curved beneath exognath. Chelipeds 
heterochelous, long, arched upward in middle, more or less keeled, granulate between 
keels, granules becoming larger and tending toward small spines on keels. Right claw 
slightly larger than left, less well keeled, possessing three large button-like teeth on the 
fixed finger, teeth are capped by dense enamel-like material. Left claw slightly smaller, 
more keeled, possessing shearing teeth on fixed finger. Upper surface of right propodus 
has three rows of spines; an inner row of four, a middle row of 7?, and an outer row 
of 7. Meri of both claws have two anterior and four posterior downward facing, and 
three or four forward facing, spines. Carpals have three or four longitudinal spine rows, 
small spines on upper surfaces and one large forward facing spine in proximal anterior 
row. Dactyli closely opposed to fixed fingers, similarly toothed, having an anterior row 
of at least five spines and one proximal posterior spine on upper surfaces. Walking legs 
long and flattened; P2 present only on the holotype, is largest and almost round; P3 and 
P4 are very flat, similar in size, smaller than ?,, larger than P5, which is also very flat 
and has a merus nearly as long as its broad carpus and propodus, and narrow dactylus. 

Comparison. — Ichocarcinus xestos is the only species in the genus and is unlikely 
to be confused with any other fossil carcineretid crabs as discussed in the generic 
comparisons. Icriocarcimis xestos is most similar to Longusorhis cuniculosis Richards 
(1975) although it differs in many significant ways: by being proportionally wider; by 



252 



having a concave front; by having a non-grooved, narrower rostrum, having its widest 
point further back; by having a straighter hind margin; by having flat areolations; by 
having an anterior transverse ridge near the posterior of the protogastric regions; and 
by having more elongate upwardly arched, keeled chelae. 

Remarks.— During preparation, the exceedingly thin and fragile exoskeleton was 
observed over the carapace. This exoskeleton is covered by swirling patterns of fine 
granules and setal pits. It is thicker on the chelae but thinner over the other pereiopods. 
The thin exoskeleton is consistent with a burrowing mode of life as evidenced by 
paratype 4 (26040). Longusorbis cuniculosis Richards (1975) is also a burrowing form. 

Superfamily Xanthoidea Dana 1851 

Family Xanthidae Dana 1851 

Xandaros, new genus 

Type species. — Zanthopsis sternbergi Rathbun 1926. 

Diagnosis. —C2iV2LX)2LCQ slightly wider than long, transversely oval, widest at anterior 
third, moderately differentiated by grooves, arched longitudinally. Rostrum short, 
downturned, sulcate and bifid. Anterolateral margins tightly rounded; orbits large. 
Posterolateral margins broadly rounded; posterior margin narrow, concave, slightly 
upturned. Carapace transversely ridged with a gastric ridge, an epibranchial ridge, and 
a mesobranchial ridge, each surmounted by low bosses. Gastric ridge with four small 
anterior bosses in diamond shape on anterior tongue of mesogastric and epigastric 
regions, a large boss at posterior portion of mesogastric region, and two transversely 
elongate bosses across cardiac region. Abdomen large, somites increasing in length 
posteriorly. Chelipeds massive, equal; merus, carpus, and propodus tuberculate; claws 
strongly convex with five longitudinal rows of tubercles; fingers spatulate at tips. 

EtymologyK—/K massively armored crab armed with huge claws; hence its name, 
"Xandaros," Greek, meaning fabulous sea monster. 

Comparison.— Xandaros exhibits the transversely oval carapace, well-developed 
orbits, dentate anterolateral margins, and ambulatory fifth pereiopods of the Xanthidae 
(Glaessner 1 969:R5 1 5). Xandaros is most similar to the Brazilian late Cretaceous genus 
Palaeoxanthopsis Beurlen 1958 in having a convex anterior margin, large orbits, and 
transverse rows of bosses on the carapace. Xandaros differs from Palaeoxanthopsis by 
lacking the prominent posterolateral spines, being relatively shorter in relation to width, 
and lacking carinate claws. Xandaros is much larger and more robust than Xanthilites 
Bell 1858 and lacks the prominent anterolateral teeth, small, covered orbits, and smooth 
claws o^ Xanthilites. Xandaros is much larger, much more robust, much more convex, 
and much more areolated than the North American late Cretaceous genus Xanthias 
Rathbun 1897. Xandaros somewhat resembles the genera Syphax A. Milne Edwards 
1864 and Titanocarcinus A. Milne Edwards 1864 in carapace shape, possession of large 
orbits, convexity, and degree of carapace areolation; but differs from them by being 
relatively broader, having carapace bosses arranged in transverse rows, and having 
significantly diflferent patterns of carapace areolation. Xandaros superficially resembles 
Xanthopsis McCoy 1849 in carapace outline and carapace bosses; but differs greatly in 
areolation, possession of transversely aligned, rather than longitudinally aligned bosses, 
lack of fusion of abdominal somites 3-5 (seen in Zanthopsis; Glaessner 1969:R522), 
and possession of a "greater number and different disposition of tubercles . . ." on the 
claws (Rathbun 1926). 



Xandaros sternbergi (Rathbun 1926) 
Figures 3E-H; 4 

Zanthopsis sternbergi Kz.\\\hur\ 1926, p. 54, PI. 39, figs. 1-4. 
Decapoda indeterminant; Sundberg and Riney 1984, p. 105, figs. 3, 9. 
Zanthopsis sternbergi Rathbun; Bishop 1986Z?, p. 128, fig. 10a, b. 



253 






Figure 4. Xandaros sternbergi (Ralhbun 1 926). A, topotype, SDSNH 26035, anterior view of carapace and 
right claw; B, topotype, SDSNH 26034, outer face of left claw; C, topotype, SDSNH 26035, dorsal view of 
carapace and right cheliped; D, topotype, SDSNH 26033, ventral view of sternum, abdomen, cheliped, and 
pereiopods; E. hypotype. EH-2. anterior view of whole crab mostly encased in calcareous concretion (note 
spatulate finger occlusion); F, topotype, SDSNH 26036, left oblique view of cheliped and carapace. Bar 
scales = 1 cm. 



254 



Types.— The holotype (USNM 73390) and six specimens from the San Diego 
Natural History Museum are apparently from the same general area, making the SDSNH 
specimens topotypes. Thomas Demere (personal communication, 22 March 1985) has 
stated "The locality description in Rathbun (1926:21, 54) is slightly in error as it states 
that Kelly's Ranch is 5 miles north of Carlsbad Station. In reality, the ranch was located 
east of Carlsbad. Cretaceous strata are exposed in only a small 'window' at the eastern 
border of the old ranch, and I am certain that the holotype of Zanthopsis sternbergi is 
from the same section as that recently exposed by grading at the Carlsbad Research 
Center." 

Occurrence, sample size, and preservation. —Ten specimens of Xandaros sternbergi 
are known from two localities, seven from the type area and three from Punta San 
Jose, Baja California (Bishop, 1986<2). The type locality is cited (Rathbun 1926) as 
"California: Kelly's Ranch, 5 miles north (sic) of Carlsbad Station, Santa Fe Railway, 
San Diego County. ..." A second suite of specimens was collected from the site of the 
Carlsbad Research Center (SDSNH Loc. 3162) in claystones of the Point Loma For- 
mation (Sundberg and Riney 1984). 

Description.— Carapace oval; width twice length, widest at midpoint across epi- 
branchial regions (Table 2); strongly arched longitudinally; slightly arched transversely. 
Orbitofrontal margin large (65% of carapace width), arcuate, with a large outer fossa 
and a poorly defined inner, antennal fossa; upper margin upturned with a sulcus at 
intraorbital septum. Rostrum short, downtumed, sulcate and bifid. Anterolateral mar- 
gins tightly rounded to widest point at epibranchial lobes; posterolateral margins rel- 
atively straighter, slightly sinuous; posterior margin distinctly concave, slightly up- 
turned into a shelf. Carapace furrows poorly defined by broad depressions. Cervical 
depression transverse, sinuous, terminating on gastric ridge in subtle pits. A posterior 
depression, subparallel to cervical depression, lies between the epibranchial-urogastric 
and mesobranchial-cardiac regions. Longitudinal grooves even more subtle; those 
bounding gastric ridge poorly defined anteriorly, better defined posteriorly around 
posterior of mesogastric, urogastric, and cardiac-intestinal regions. Groove between 
protogastric and hepatic regions obsolete. 

Carapace differentiated into more or less tumid regions. Cephalic arch dominated 
by discontinuous transverse ridge surmounted by a row of nine bosses; a central me- 
sogastric boss on posterior of anterior tongue of mesogastric region; two on protogastric 
region; and two on hepatic region, these becoming more pronounced from proximal 
protogastric boss to distal hepatic boss. Mesogastric region with large posterior boss, 
and smaller but pronounced medial bosses at the posterior and anterior ends of the 
anterior prolongation which with small epigastric bosses form a diamond-shape. The 
margin of the orbit rises from the sulcate, bifid rostrum forming prominent orbital 
concavities in the anterolateral margin. Scapular arch dominated by sagittal, epigastric, 
and mesogastric ridges. Sagittal ridge with depressed urogastric region and raised cardiac 
region often surmounted by two low, adjacent, transversely elongated bosses. Epigastric 
ridge with prominent proximal boss and two smaller but more pronounced bosses, the 
distal one being extended into a long lateral spine. The epigastric ridge is interrupted 
by the depressed urogastric region. A second transverse scapular ridge lies on line with 
the two transverse cardiac bosses, marked by a gentle swelling on the mesobranchial 
regions. Metabranchial and intestinal regions form a low, raised shelf along concave 
posterior margin. Carapace ornamented by gentle unevenness, subtle bosses, and very 
fine punctation. 

Female abdomen broad, barely grooved longitudinally, oval; somites progressively 
longer from Ab, to Ab,, widths increase to Abs then decrease to telson; segments Aba 
to Abj with paired groups of setal pits (consisting of three pits each) near posteriors. 
Male abdomen narrower, segments more nearly similar to one another. Pereiopods 
variable; P, very large, massively chelate; P2-P5 progressively smaller, oval in cross 
section. Telson of female broadly subovate in contrast to triangular telson of male. 

Chelipeds very large, massive, and tuberculate, subequal, right somewhat larger. 
Merus long, armed with about five ventral tubercles. Carpus equant, longitudinally 



255 



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256 



grooved, tuberculate; four? longitudinal rows of tubercles, the uppermost row with six 
small tubercles on edge of flattened crest, second row with four larger tubercles and a 
single distal tubercle lies above the longitudinal groove; two rows of tubercles each lie 
below the longitudinal groove which runs from the upper distal articulation to the 
proximal articulation. Distal outer edge bordered by a furrow. Propodus longitudinally 
convex, strongly convex transversely on outer face. Palm longer than high, covered by 
five longitudinal rows of tubercles, the uppermost runs along the upper margin of the 
claw, the second subparallel to the upper margin with tubercles, the third with four 
tubercles, and the fourth with five tubercles form a "V" diverging distally from a 
common tubercle; the fifth row runs parallel to the lower margin. The fixed fingers are 
slim, extended horizontally, and spatulate at tips; left somewhat blunter than right. 
The movable fingers are slim, curved and spatulate, with a row of 13 setal pits from 
upper articulation to stepped-down tip. 

Comparison. —Although Xandaros sternbergi resembles many other xanthid crabs 
in a general way, few species are similar enough to cause confusion. Xandaros sternbergi 
is perhaps most similar to Palaeoxanthopsis cretacea (Rathbun 1 902) from the Maas- 
trichtian of Brazil, but differs from it by lacking the large, prominent posterolateral 
spines, by being relatively shorter, by having three medial mesogastric bosses rather 
than one, by having its posterior medial mesogastric tubercle and the posterior part of 
the mesogastric region more anteriorly placed, by its transverse epigastric ridges with 
a row of three bosses, by its transversely bilobed cardiac region, and by its lack of 
"carinate" chelae. Xandaros sternbergi can easily be distinguished from Syphax crassus 
A. Milne Edwards 1864, Titanocarcinus serratifrons A. Milne Edwards 1863, and 
Xanthilites bowerbanki Bell 1858 by differences in carapace shape, areolation, and 
surface ornamentation. Xandaros sternbergi is easily distinguished from Zanthopsis 
hendersonianus Rathbun 1926 from the Oligocene of California and Zanthopsis vulgaris 
Rathbun 1926 from the Oligocene of the northwestern U.S. and southwestern Canada. 



Significance 

The two taxa described enhance our still limited knowledge of Pacific Slope Cre- 
taceous decapods. Xandaros sternbergi is now much better known with the description 
of its body and its assignment to a new genus. Icriocarcinus xestos not only represents 
a new taxon from the Pacific Slope but provides important insights into the possible 
origin of some trace fossils in the Cretaceous. Both taxa are now relatively well known 
species because of the large collections available and the completeness of the specimens. 
The addition of the Baja California collection enlarges the paleobiogeographic distri- 
bution of Xandaros sternbergi. 



Acknowledgments 

I am indebted to Edward Hennessey of Long Beach, California, for making his 
collection of Baja California crabs available for study. Thomas A. Demere, Mark 
Roeder, and Bradford Riney of the San Diego Natural History Museum collected and 
made the Carlsbad decapod collection available to me. The Koll Construction Company 
of San Diego cooperated in the conservation of the Carlsbad fossil collection. The 
manuscript was strengthened by critiques provided by Thomas A. Demere and Joseph 
Collins, London. The manuscript was typed by Donna Cain and Judith McQuaig. 
Photographic assistance was rendered by Jeanne Amos and Frank Fortune. Indirect 
support was provided by the National Science Foundation (DEB 801 1570), National 
Geographic Society (2867-84), and the Georgia Southern College Faculty Research 
Committee. My sincere thanks is extended to each person for his or her assistance in 
the production of this paper. 



257 



Literature Cited 



Bell, T. 1858. A monograph of the fossil mala- 
costracous Crustacea of Great Britain. Pt. I, 
Crustacea of the London Clay, pages 10-40. 
Palaeontographical Society London. 

Beurlen, K. 1958. Contribuicao a paleontologia 
do estadodo Para. Crustaceos decapodos da 
Formacao Pirabas 1 (Arthropoda-Crustacea). 
BoUcttino del Museu Goeldi (Paraense) new 
series, Geologica. 

Bishop, G. A. 1983. Two new crabs. Nolopocory- 
stes (Eucorystes) eichhorni and Zygastrocarci- 
nus griesi (Decapoda:Brachyura) from the 
Bearpaw Shale (Campanian) of north-central 
Montana. Journal of Paleontology 57:900-910. 

Bishop, G. A. 1986(3. Taphonomy of the North 
American decapods. Journal Crustacean Bi- 
ology 6:326-355. 

Bishop. G. A. 1986/7. Occurrence, preservation, 
and biogeography of the Cretaceous Crabs of 
North America. Pp. 111-142 //; R. H. Gore 
and K. L. Heck (eds.). Crustacean Biogeogra- 
phy, Crustacean Issues 4. A. A. Balkema, Rot- 
terdam, The Netherlands. 

Feldmann, R. M., and C. B. McPherson. 1980. 
Fossil decapod crustaceans of Canada. Geo- 
logical Survey of Canada Paper 79-16. 

Glaessner, M. F. 1929. Crustacea Decapoda: Fos- 
silium Catalogus, Part 4 1 . W. Junk, Berlin, West 
Germany. 

Glaessner, M. F. 1969. Decapoda. Pp. 626-628 
in R. C. Moore (ed.). Treatise on Invertebrate 
Paleontology. Geological Society of America 
and University Kansas Press, Lawrence, Kan- 
sas, USA. 

McCoy, F. 1849. On the classification of some 
British fossil Crustacea with notices of new 
forms in the University collection at Cam- 
bridge. Annals and Magazine of National His- 
tory 2:161-179. 

Milne Edwards. A. 1862-65. Monographic des 
crustaces de la famille Carcerines. Annales des 
Sciences Naturelles, Zoologie. ser. 4, 1 8( 1 862): 
31-85, 20(1863):273-324, ser. 5, 1(1864):31- 
88, 3(1865):297-351. 

Milne Edwards, A. and P. Brocchi. 1878-79. Note 
sur quelques Crustaces fossiles appartenant au 
groupe des Macrophthalmiens. Bulletin de la 
Societe Philomathique de Paris (3):113-117. 

Milne Edwards, H. 1834-40. Histoire Naturelle 
des Crustaces. Paris 



Rathbun, M. J. 1897. Synopsis of the American 
species of fa //r(/\ Philippi ( = Cynip<)solta Roux). 
Proceedings of the Biological Society of Wash- 
ington 11: 109- no. 

Rathbun, M. J. 1902. In J. Branner. Geology of 
the northeast coast of Brazil. Bulletin Geolog- 
ical Society of America 13:41-98. 

Rathbun, M. J. 1908. Descriptions of fossil crabs 
from California. Proceedings of the United 
States National Museum 35:341-349. 

Rathbun, M. J. 1926. The fossil stalk-eycd Crus- 
tacea of the Pacific Slope of North America. 
Bulletin of the United States National Museum 
138:1-155. 

Rathbun, M. J. 1935. Fossil Crustacea of the At- 
lantic and Gulf Coastal Plain. Geological So- 
ciety of America Special Paper 2. 

Richards, B. C. 1975. Longiisorbis cuniculosis: A 
new genus and species of Upper Cretaceous 
crab; with comments on Spray Formation at 
Shelter Point, Vancouver Island, British Co- 
lumbia. Canadian Journal of Earth Science 12: 
1850-1863. 

Stenzel, H. B. 1953. Decapod crustaceans from 
the Woodbine Formation of Texas. United 
States Geological Survey Professional Paper 
242:212-217. 

Sundberg, F. A., and B. O. Riney. 1984. Prelim- 
inary report on the Upper Cretaceous macro- 
invertebrate faunas near Carlsbad, California. 
Pp. 103-107 in P. L. Abbott (ed.). Upper Cre- 
taceous Depositional Systems of Southern Cal- 
ifornia and Northern Baja California. Pacific 
Section Society of the Economic Paleontolo- 
gists and Mineralogists Fieldtrip Guidebook 
36. 

Van Straelen, V. 1934. Contribution a letude des 
crustaces decapodes fossiles de la Catalogne. 
Geologique Pays Catalans 3:1-6. 

Withers, T. H. 1922. On a new brachyurous crus- 
tacean from the Upper Cretaceous of Jamaica. 
Annals and Magazine of Natural History 10: 
534-541. 

Woodward, H. 1896. On some Podophthalma- 
tous Crustacea from the Cretaceous Formation 
of Vancouver and Queen Charlotte Islands. 
Quarterly Journal of the Geological Society of 
London 52:221-228. 



f"^ 



■(^ 




TRANSACTIONS 
IVICZ OF THE SAN DIEGO 

LIBRARY SOCIETY OF 

NATURAL HISTORY 

FEB 2 1 1889 

HARVARD 
VDrOTtie' 2r RTUmbferi 6 pp. 259-273 1 5 February 1 989 



A new abyssal hydrothermal verrucomorphan (Cirripedia; Sessilia): 
The most primitive living sessile barnacle* 

William A. Newman and Robert R. Hessler 

Schpps Institution of Oceanography A-002, La Jolla, California 92093 and Natural History Museum, P.O. 
Box 1390. San Diego. California 92112 USA 

Abstract. A remarkable sessile barnacle, Neoverruca brachylepadoformis gen. et sp. nov., has been 
discovered living near abyssal hydrothermal vents at 3600 m in the Mariana Back-Arc Basin, Western 
Pacific. It has closer affinities with the earliest known sessile barnacles, the Brachylepadomorpha (?Upper 
Jurassic-Miocene), than with any of the fossil or extant Balanomorpha (Upper Cretaceous-Holocene). 
Thus Neoverruca, the most primitive living sessile barnacle, is a "living fossil." However, there are 
subtle characteristics of its shell that are diagnostic of the asymmetrical sessile barnacles, suborder 
Verrucomorpha (?Middle, Upper Cretaceous-Holocene). In having verrucomorphan specialization su- 
perimposed on the brachylepadomorphan plan, Neoverruca constitutes a "missing link" between these 
two suborders. As the sole surviving member of an ancient radiation, Neoverruca adds significantly to 
our knowledge of the origin and evolution of sessile barnacles and the nature of their pedunculate 
ancestor. Furthermore, it heightens our appreciation of the role abyssal hydrothermal environments 
play in perpetuating ancient forms whose wide-ranging, predominantly shallow-water ancestors have 
long been extinct. 

Introduction 

A little more than a decade ago communities of large clams, mussels, tube worms, 
and other animals were discovered at depths of 2600 m or so, clustered around abyssal 
hydrothermal vents of the Eastern Pacific, near the Galapagos Islands and at 21°N off 
Mexico (Hessler and Smithey 1983, Jones 1985). The latter locality provided the first 
vent barnacle, Neolepas zevinae {see Newman 1979), and '^O determinations subse- 
quently confirmed that it was living in waters several degrees above ambient (Killingley 
and Newman 1982). 

Neolepas, a well-armored form having an apparent fossil record dating from the 
?Lower Jurassic of New Caledonia (Buckeridge and Grant-Mackie 1985), is the most 
primitive living scalpelloid and the sole surviving member of the Eoscalpellidae (Lower 
Triassic; Buckeridge 1983). Other than its primitive arrangement of capitular plates, 
Neolepas is specialized in having appendages that differ from those of all shallow-water 
as well as deep-sea scalpelloids in being adapted for feeding on extremely fine suspended 
material transported by gentle currents (Newman 1979). 

Additional populations of the same species of Neolepas were subsequently dis- 
covered by French scientists at the same depth from 13°N off Mexico (Newman 1985). 
However, although recruitment on artificial substrates placed in the area has been 
conspicuous (C. van Dover, personal communication), all collections have yielded little 
more than a dozen adult specimens. Therefore, while Neolepas is evidently endemic 
to hydrothermal vents in the East Pacific, it is a relatively inconspicuous member of 
the communities found there. 

The new form, Neoverruca brachylepadoformis gen. et sp. nov., differs from Neo- 
lepas not only in being sessile but in being one of the most abundant and conspicuous 



* Contribution of the Scripps Institution of Oceanography, new series. 



260 

members of the macro-fauna of the hydrothermal vents at 3600 m in the Mariana 
Back-Arc Basin, Western Pacific, and this fauna differs in other ways from those seen 
in the Eastern Pacific {see Hessler et al. 1988). Nonetheless, Neoverruca is ecologically 
similar to Neolepas in being completely armored and provided with delicate appendages 
adapted for feeding on very fine material transported by gentle currents {see Anderson 
1980 and Zevina 1988, and Anderson and Southward 1987, concerning feeding in 
Verruca and cirripeds in general, respectively). 

Neolepas and Neoverruca are the most primitive living members of their suborders, 
the Scalpellomorpha and Verrucomorpha, respectively, both of which first appear in 
the Mesozoic. Thus, these genera are relics' surviving in the refugia provided by abyssal 
hydrothermal springs long after their less specialized Mesozoic ancestors went extinct. 

Description 

Suborder Verrucomorpha Pilsbry, 1916, U. Mesozoic-Recent 
(For an amendment of the suborder and a proposal for new families within it, see 
the systematic section below.) 

Neoverruca Newman, gen. nov. 

Diagnosis. —N Qrr\xcomov^\\3. {see systematic section below) having several whorls 
of small, imbricating plates surrounding the base and elevating the wall above sub- 
stratum, and with a median latus interposed between scutum and tergum of the movable 
side. Type: Neoverruca brachvlepadoformis. Etymology: A new {neo, G.) wart {verruca, 
L.). 

Neoverruca brachylepadoformis Newman, sp. nov. 
Figures 1, 2, 3, and 4C-1 

Diagnosis.— As for the genus, although the median latus becomes rudimentary 
with growth and may be completely corroded away in old individuals. The scuta have 
internal, apical teeth; the appendages are modified for feeding on extremely fine particles 
{see Newman 1979), and there is a median-dorsal filamentary appendage and a pair of 
ovigerous fraena, but caudal appendages are absent. Etymology: Short-shellfish {brachy- 
lepas, G.) form {form, L.). 

Material.— More than 100 adult hermaphrodites and 12 or so juvenile stages 
attached to ferriferous crusts and vent mussels near hydrothermal springs of the Mariana 
Back-Arc Basin in the Western Pacific (18°12'N; 144°42'E) at depths of approximately 
3600 m. ALVIN Dives (Stations) 1822, 1840, and 1844, April 1987. Temperature field 
from 5 to 15°C (Hessler et al. 1988). 

Deposition of types.— Holotype U.S. National Museum of Natural History Cat. 
no. 240030, and two paratypes to each of the following institutions: USNM Cat. no. 
240031; British Museum (Nat. Hist.) Reg. no. 88.274-275; National Museum Nat. 
Hist. Paris, Ci 2050; University of Auckland; Zool. Mus. Copenhagen; Zool. Mus. 
Moscow State University; National Sci. Mus., Tokyo. 

Hard parts. —Asymmetry of the shell in verrucomorphs involves ontogenetic changes 
in the proportions and the arrangement of the plates, and individuals can be either 
right or left sided. For ease of description and discussion both sides are illustrated as 
though they were right sides (except in Fig. 2) and identified as follows: The side 
supporting the movable tergum and scutum (operculum), and where the rostrum and 
carina come in contact, will be called the "movable side." The opposite side, where 
the gap between the rostrum and carina is filled by the fixed scutum and tergum, will 
be called the "fixed side." 



' The term "relic" is used here to specify a survivor of an ancient lineage, in contrast to a "relict" or 
subpopulation isolated from a parent population by some vicariance event (see Udvardy 1969:208 for 
discussion). 



261 



These designations, "movable and fixed sides," apply to all verrucomorphans and 
distinguish their unique morphology from that of the symmetrical sessile barnacles. 
However, if a specimen of Neovcrruca brachylepadofonnis were viewed from one side 
or the other, while the nature of the opposite side remained unknown, it would be 
diagnosed as a brachylepadomorphan. Furthermore, without the more detailed infor- 
mation on and illustrations of the opercular parts and wall presented here, it would be 
difficult to decide if a mixed sample of disarticulated plates from several individuals 
of this species represented a neoverrucid or a brachylepadomorphan, as was the case 
with a number of fossil shell lots assigned by Darwin to a pedunculate barnacle, Pol- 
licipes, before Withers (1914a) recognized them as a new and primitive brachylepa- 
domorphan, Pycnolepas. Thus, it is possible that some fossils considered brachylepa- 
domorphans may actually represent neoverrucids. 

The movable side, supporting the movable scutum and tergum, tends to be flattened 
or slightly concave in the vertical plane, while the fixed side is somewhat rounded. 
Depending on the circumstances under which an individual grew, the scuta and terga 
may tilt from essentially vertical, as in Altivermca, toward the fixed side, as in Verruca. 
There is no obvious shortening of the fixed scutum and tergum relative to the movable 
scutum and tergum in tilted individuals of Neoverruca, although the tilt can approach 
80° in crowded individuals, bringing the plane of the scuta and terga nearly parallel to 
the substratum. 

There are usually four whorls of relatively small imbricating plates discernible on 
the movable side and two or three on the fixed side of the animal. In Brachylepas {see 
Newman 1987 and Zullo et al. 1987), and perhaps in most Pycnolepas (J. S. H. Collins, 
personal communication), there are more whorls of plates, and the plates of the lower 
whorls possess mortises that interlock with tenons in plates of alternate lower whorls. 
When viewed from within, or when disarticulated, no interlocking between imbricating 
plates can be observed in Neoverruca\ to the contrary, there appears to be a tendency 
for some plates of the lowermost whorl to be lost with growth and age. 

At the rostral and carinal ends of the shell, the height the latera extend up the wall 
diminishes. There is a subrostral and subcarinal tier of plates, and between them there 
appear to be 10 to 12 tiers of latera on the movable side and 6 to 7 tiers on the fixed 
side. Thus there are apparently as many as 1 8 vertical tiers of imbricating plates around 
the circumference of the wall, standing two to four whorls high and supporting the 
principal wall plates above the substratum. This is about the number of tiers encoun- 
tered in Chionelasmus and in the basic shell of Catophragmus. On the other hand, it 
is about half the number of tiers estimated for the highly derived interlocking imbri- 
cation plates of Brachylepas cretacea {see Newman 1987). 

The individual plates of the imbricating basal whorls in Neoverruca have much 
the same shape and ornamentation: Each is a more or less equilateral triangle with a 
generally faint, narrow median ridge flanked on either side by fine striations that radiate 
from the apex to the base. The median tier of latera, below the median latus, covers 
the rostro-carinal suture on the movable side. But it takes several tiers of latera to cover 
the suture between the scutum and tergum, and the adjacent sutures between them and 
the rostrum and carina, on the fixed side {see Figs. lA and B, 2B, and 4C-1). 

The apically acute median latus, interposed between the movable scutum and 
tergum, becomes rudimentary, badly corroded, and weakly attached with age, and it 
may be lost in older individuals {see Figs. 4C-1 and 2B). A median latus in this position 
is unknown in other sessile barnacles except brachylepadomorphans. 

Attempts to identify individual latera in adults were confusing. Part of the con- 
fusion arose because some of the marginal imbricating plates are easily lost. But the 
full extent of the confusion was not understood until the ontogeny of a number of the 
post-cyprid metamorphic stages was studied (Newman 1989). Some information 
on the remarkable juveniles of Neoverruca is given below, under "Juvenile Stages," 
but determination of homologies and identification of the principal latera, based on 
the ontogenetic analysis, are beyond the scope of this species description and will be 
published separately (Newman 1989). 



262 




Figure 1. Neoverruca brachylepadoformis gen. et sp. nov. Large individual (2.1 cm high) from a closely 
packed aggregation at ALV Sta. 1843. For ease of comparison, both sides appear as right sides. Note lack 
of ferromanganese deposits on younger portions of shell of the adult and on the two juvenile individuals in 
A. See Figure 4C- 1 for the form of an adult growing under uncrowded conditions (please consult Fig. 2 for 
identification of plates and the caption of Fig. 4 for symbols). 

A, view of the fixed (FS-FT) side. Note that R and C are moderately separated, with S and T immovably 
fixed between them. The two recently settled juveniles both with movable (MS-MT) sides outward, first 
attached themselves in the depression formed by the articulation between FS and FT. It can be observed 
that the lower, younger juvenile appears to be basally narrower; it is a pedunculate stage with naked 
peduncle and typical scalpellomorphan capitulum having a relatively narrow carina and rostrum. The upper, 
older juvenile has undergone metamorphosis into the sessile mode, and it has added several more whorls of 
imbricating plates to the expanded basal margin of its capitulum. 

B, view of the movable (MS-MT) side. Note that R overlaps C and that the relatively narrow S and T 
form a movable operculum. The median latus (L), visible on the MS-MT side of the juveniles (Fig. lA) and 
the uncrowded adult (Fig. 4C-1; MS-MT), becomes vestigial with growth and, owing to corrosion, may 
completely disappear in large adults as it almost has here {see Fig. 2B). 



The basis is membranous. When individuals are severely crowded, the basis can 
elongate to the extent that, when individuals are separated, some resemble pedunculate 
barnacles. The elongation may also include the lower portion of the wall, causing some 
of the lowermost plates of the imbricating whorls to separate from each other, furthering 
a pecundulate semblance. Elongation of bases, both membranous and calcareous, occurs 
in a number of distantly related sessile barnacles for a variety of adaptive reasons that 
include crowding. We consider elongation of the basis in Neoverruca, in response to 
crowding, to be without phylogenetic significance. 

The scuta and terga are weakly ornamented, the terga by a more or less median 
ridge and fine longitudinal ribs or striations radiating from the apex, the scuta similarly 
but without a median ridge. The scutum and tergum of the fixed side are proportionately 
wider than their movable counterparts {see Fig. 2C, D and E, F, respectively). The 
movable pair fit within the confines of the margins of the fixed pair, and the scutum 
forms the basal hinge line high up on the lateral portions of the rostrum and carina. 

The rostral angle of the fixed scutum is rolled inward (Fig. 2C) to form a condyle 
with the relieved rostral angle of the movable scutum (Fig. 2E). The interior of the 
apical region in both scuta, above the deep depressions for the scutal adductor muscle, 
is thickened; the thickening of the fixed scutum is produced into a short, longitudinal. 



263 




Figure 2. Neoverruca hrachylepadofonnis gen. et sp. nov. (ALV Sta. 1 843). A and B, adult viewed from 
the left (fixed) and right (movable) sides, respectively. C and D, and E and F. interior views of FS and FT. 
and MS and MT, respectively, but from a slightly smaller individual. Note narrowness of MS and MT (E 
and F), as compared to those of the fixed side (C and D), and the unusual tooth-like structures in the apices 
of the scuta (C and E). Also note contact between R and C, and vestigial L between MS and MT, on the 
movable side (B). 



depending tooth or ridge that comes to rest just over, or on, one or two similarly formed 
ridges on the movable scutum. These ridges, the condyle, and the fit along the occludent 
margins of the movable pair within the fixed pair assure alignment of the operculum 
with the wall and lock it in place when closed. The relationship of the scutal adductor 



264 



A,C,E& F 0.25mm 




Figure 3. Neoverruca brachylepadoformis gen. et sp. nov. (ALV Sta. 1 843). A, labrum flanked by mandibular 
palps, setae on left palp deleted; B, crest of labrum enlarged; C, mandible; D, spines of second and third 
tooth enlarged; E, first maxilla; and F, intermediate articles of sixth cirrus (some setae truncated to simplify 
illustration) (note the two anomalously short articles between the two normal ones). 



muscle to these ridges has not been examined, and therefore some apodemal properties 
of the latter cannot be discounted, but these ridges and associated depressions are 
internal and are not involved with housing complemental males. The articular margins 
between the scutum and tergum of each side lack the well-developed articular ridges 
and furrows seen in some scalpelloids, most verrucomorphans, and virtually all bal- 
anomorphans. 

The rostrum and the carina, also marked by fine ribs or striations that radiate 
from apex to base, are slightly asymmetrical and perceptibly flat on the movable side. 
The flattened condition could aid in their identification as "neoverrucid" when dis- 
articulated. The carina is generally but not necessarily higher than the rostrum. Like 
the rostrum, it has shallow depressions around its perimeter marking the positions of 
the vertical tiers of imbricating plates, but the depressions are not as pronounced or 
arranged in as precise a manner as in Brachylepas cretacea. The carina also has an 
"alar" furrow or depression on the movable side that superficially appears to have been 
formed in response to overlap by the rostrum, but when an articulated specimen is 



265 

viewed from within, it is seen to accommodate the carinal portions of lower latera. 
Overlap between the rostrum and carina, established during ontogeny, is apparently 
never marked; it is the lower latera that provide protection and strength to this suture. 
Concomitantly, there is also a broad but shallow furrow on the carinal margin of the 
rostrum to accommodate them. 

The lateral margins of the rostrum and carina on the fixed side are provided with 
narrow, smooth, articular surfaces to receive the corresponding margin of the scutum 
and the basi-carinal margin of the tergum, respectively. A large latus tends to overlap 
the rostro-scutal, scuto-tergal, and tergo-carinal sutures. But, for strength and protection 
of the more numerous sutures found on the fixed side, there are more tiers of imbricating 
latera than on the movable side. On the other hand, the movable side tends to have 
more whorls than the fixed side, especially in very young individuals that are bent over. 
Soft parts. —The prosoma (cephalic region supporting mouth parts) is uninflated and 
blends imperceptibly into the thorax, as in Verruca. However, it bears an anteriorly 
directed, median dorsal filamentary appendage containing ramifications of the testes. 
The mouthparts are very similar to those of the hydrothermal scalpelloid Neolepas: 
The labrum is slightly bullate; the crest is concave, without a notch, and supports a 
single row of fine, sharp teeth behind a row of debris-laden bristles, and the palps are 
relatively small (Fig. 3A, B). The mandibles are clothed with fine setae, and the cutting 
edge consists of one strong superior spine and three low, broad teeth each supporting 
a single row of fine, sharp spines along their superior margins. The fourth tooth blends 
almost imperceptibly into the spiny lower margin, and the inferior angle is produced 
into a fine-toothed comb of similar spines that change to fine, soft spines along the 
inferior margin (Fig. 3C). The first, and second (not illustrated), pair of maxillae each 
have a straight cutting edge supporting a comb of fine setae (Fig. 3E). Behind the second 
maxillae, a subesophageal salivary gland apparently opens on a prominent median 
papilla. 

The first two pairs of cirri are modified as maxillipeds; the rami of the first pair 
have inflated, heavily setose proximal articles and subequal, antenniform distal articles, 
and they have about 25 articles each; the second pair are similar in appearance but 
their rami, of about 14 and 34 articles each, are markedly unequal. The remaining four 
pairs of cirri are ctenopod (Fig. 3F) and have long, slender rami of about 52, 70, 84, 
and 75 articles per ramus, respectively; the proximal articles are wider than long and 
support one or two pairs of setae, while the distal articles are three times as long as 
wide and support as many as eight pairs of setae along the lesser curvature (Fig. 3F). 
The probosciform penis is as long as the posterior cirri, and caudal appendages are 
absent. 

Approximately 100 large (0.25-0.50 mm) eggs, in a pair of saucer-shaped ovigerous 
lamellae held in the bottom of the mantle cavity by a pair of ovigerous fraena, were 
found in three of the five individuals examined internally; embryos from one individual 
consisted of nauplii with well-developed appendages and caudal spines, but whether 
they are released as feeding or non-feeding nauplii, or as cyprids, remains unknown. 

Juvenile Stages 

A number of ontogenetic stages following cyprid metamorphosis were found at- 
tached primarily to established hermaphrodites (adults), and, as noted above, they will 
be described in more detail elsewhere (Newman 1989). Juveniles found on adults 
were most commonly attached along the articulation between the tergum and scutum 
of either side (Fig. lA), a position where they receive protection from the adults when 
crowded, and a position that could be advantageous should they develop precociously 
as males {see Charnov 1987 and Klepal 1987). 

Following cyprid metamorphosis, juveniles pass through several pedunculate stages, 
and those developing on the surface of adults orient in the same direction as the adult 
before undergoing metamorphosis into sessile juveniles. If a sessile juvenile is attached 
to the right side of an adult, its movable side will be the right side, but if it settles on 



266 




Figure 4. Origin and radiation of the sessile barnacles. The four major radiations in this diagram are 
distinguished by major evolutionary innovations: A, the development of a complex capitular armament, by 
transfer of peduncular plates to the capitulum, in scalpellomorphan Pedunculata (note three latera in A-2 
between R and C); A to B, advent of the Sessilia or sessile barnacles (Brachylepadomorpha) by elimination 
of the peduncle and further development of a modest separation between an operculum and the remaining 
capitular plates (note that three tiers of latera close the gap between rostrum and carina); B to C, divergence 
of the asymmetrical sessile barnacles, Verrucomorpha, by fixation of S and T (FS and FT) between R and 
C of one side, the joining of R and C to support S and T (MS and MT) of the movable side, and the subsequent 



267 



the left side of the aduU, its movable side will be the left side. Thus, right or left 
sidedness is ecotypically determined, and this is likely the case in other verrucomor- 
phans in which right and left sidedness occurs in the same species. 

The peduncle is naked in the pedunculate juvenile stages, and, in the earliest, the 
capitular plates are symmetrically arranged, all as in the early juveniles of scalpello- 
morphans. Capitular asymmetry gradually becomes evident through differential ap- 
pearance and growth of the plates and the heterochronous appearance of the first whorl 
of latera before the median latus on the incipient movable side. When the essential 
transformations heralding the verrucomorphan asymmetry are completed, the last pe- 
dunculate juvenile undergoes an abrupt metamorphosis into the first sessile juvenile. 
While distinct pedunculate stages are unknown in the ontogeny of other sessile bar- 
nacles, Darwin (1854) noted the semblance of a peduncle during metamorphosis from 
the cyprid to the first juvenile in Semibalanus balanoides. 

Systematics 

Subclass Cirripedia Burmeister, 1834 

Superorder Thoracica Darwin, 1854, ?Cambrian, Silurian-Recent 

Order Sessilia, Upper Mesozoic-Recent 

Suborder Verrucomorpha Pilsbry, 1916 (amended) 

Asymmetrical sessile barnacles, the primary walls of which consist of a chamber 
formed by the rostrum and carina abutting on one side and a scutum and tergum 
interposed and fixed between them on the opposite or "fixed" side, and closed by the 
movable scutum and tergum or operculum (Darwin 1854, Verruca sensu lato, see Fig. 
4C-3 herein); the wall is sometimes provided with a pair of latera (rostro- and carino- 
latus) on the movable side (Withers 1914Z), Eoverruca and Proverruca, see Fig. 4C-2 
herein), or it is surrounded by several basal whorls of small, imbricating plates elevating 
the principal wall plates above the substratum and includes a median latus interposed 
between the scutum and tergum of at least the movable side (Fig. 4C-1, Neoverruca 
gen. nov.). 

As can be seen from this diagnosis, and as depicted in Fig. 4C, the verrucomorphans 
fall into three natural groups, beginning with the new form (superficially indistinguish- 
able from the Brachylepadomorpha) and ending with the familiar and highly modified 
form on which the suborder was founded {Verruca s. 1., including allied genera listed 



loss of all latera, bringing the principal wall plates into contact with the substratum; B to D, divergence of 
the higher symmetrical sessile barnacles, the Balanomorpha, by closing of the gap on both sides, between R 
and C, with a few enlarged and specialized latera and, concomitantly, by bringing R and C and the principal 
latera into contact with the substratum. The median latus (L) was known to go with the operculum in 
brachylepadomorphs, it is now known to do likewise in the verrucomorphs; and it was inferred to do so in 
the primitive balanomorph, Catophragmus {see Newman 1987). However, the homologies of the latera of 
a very primitive balanomorphan, Chionelasmus (Fig. 4D-1) remain conjectural. 

A, Pedunculata; relevant Scalpellomorpha. A-1, Neolepas zevinae from hydrothermal vents at 2600 m, 
Eastern Pacific; A-2, Scillaelepas. a deep-sea amphitropical complex, 400-2000 m; and A-3, Capitulum 
mitella. intertidal, ?Madagascar-Westem Pacific. B, C, and D, Sessilia. B, fBrachylepadomorpha, Europe, 
North America, and Antarctica; B-1, generalized brachylepadomorphan; B-2, ■\Brachylepas cretacea,* En- 
gland. C, Verrucomorpha;** C-1, Neoverruca hrachylepadoformis gen. et sp. nov., small (1.0 cm high) un- 
crowded individual from 3600 m, hydrothermal springs, Mariana Back-Arc Basin (ALV Sta. 1840); C-2, 
■f Eoverruca hewitti. England; and C-3, Verruca, cosmopolitan, mostly deep water to approximately 5000 m. 
D, Balanomorpha; D-1, Chionelasmus darwini. deep water (approximately 500 m), islands of the Indo-West 
Pacific; D-2, generalized Catophragmus s. 1.,* extant species, intertidal, Bermuda and Caribbean islands, off- 
shore islands on the Pacific side of Panama and Costa Rica, and Southeast Australia and Tasmania; D-3, 
Bathylasmatidae (He.xelasma), Western Atlantic and Western Pacific, deep water, 100-3000 m. 

t. Extinct; *. unessential basal imbricating plates toward rostral and carinal ends omitted; **, asymmetry 
in verrucomorphans can be cither right or left sided in the same population. For ease of comparison between 
sides of these verrucomorphans, all side views are illustrated as though they were of the right side. C, carina; 
FS, fixed scutum; FT, fixed tergum; L, median latus; MS, movable scutum; MT, movable tergum; R, rostrum; 
S, scutum; and T, tergum (A, B, and D-1-2 from Newman 1987, C-2 modified from Withers 1935, C-3 
modified from Pilsbry 1916. and D-3 from Hoek 1913). 



268 

below under the Verrucidae; see Zevina 1987^). Since this evolutionary sequence has 
been achieved by reduction, it is possible that some members of Verruca s. 1. have 
descended more than once from the proverrucan and/or the neoverrucan level of 
organization. However, there is presently no morphological evidence for convergence 
at any level within the Verrucomorpha. Therefore we propose that these three groups 
be recognized at the family-group level, as follows, in order of increasing specialization: 

Neoverrucidae Newman, fam. nov. The primary wall is elevated above the sub- 
stratum by basal whorls of imbricating plates, and a median latus is interposed between 
the movable scutum and tergum (Recent, unless some fossils, particularly some already 
attributed to the Brachylepadomorpha, prove to be neoverrucids). Neoverruca gen. nov. 

Proverrucidae Newman, fam. nov. The primary wall is in contact with substratum 
and is provided with two overlapping latera protecting the rostro-carinal suture on the 
movable side (Upper Cretaceous). Proverruca Withers, \9\4b\ family includes Eo- 
v^rrwca Withers, 1935. 

Verrucidae Darwin, 1854. The primary wall is in contact with the substratum and 
is without latera of any sort (?Middle, Upper Cretaceous-Holocene). The genus Verruca 
s. 1. proved to be species-rich with the advent of deep-sea explorations, and a number 
of subgenera, presumably representing natural groups, have been erected. Zevina (1987a, 
b) has proposed that the subgenera be elevated to full generic rank. To these she added 
a new genus, and the six are listed below more or less in order of increasing special- 
ization: 

(1) Ahiverruca Pilsbry, 1916:40 (Type: V. hoeki Pilsbry, 1907; ? = F. gibbosa 
Hoek, 1883; Zevina 1987/): 18 13). 

(2) Verruca Schumacher, 1817:35 (Type: Lepas stroemia Miiller, 1776). 

(3) Cameraverruca Pilsbry, 1916:39 (Type: V. euglypta Pilsbry, 1907). 

(4) Metaverruca Pilsbry, 1916:21 (Type: V. coraliophila Pilsbry, 1916). 

(5) Rostratoverruca Broch, 1922:297 (Type: V. nexa Darwin, 1854). 

(6) Spongoverruca Zevina, 1987/7:1813 (Type: V. spongicola Gruwel, 1911). 

While derived characters are generally used to distinguish among several of these 
genera, Ahiverruca and Verruca sensu stricto are distinguished primarily on the basis 
of whether the plane of the movable plates is nearly vertical or horizontal to the 
substratum. In light of the variation observed in Neoverruca in this regard, the pos- 
sibility that some species included in these genera express comparable ecophenotypic 
variability exists, and therefore the distinction between these two otherwise unspe- 
cialized genera should probably be viewed with caution. 

The relationships of the Verrucomorpha to the symmetrical sessile barnacles, and 
the radiation of the latter, are illustrated in Figure 4, while times of first appearance 
and geologic ranges are depicted in Figure 5. 

Discussion and Conclusions 

Biogeographical and evolutionary significance. —Both hydrothermal barnacles, 
Neolepas from the East Pacific and Neoverruca from the West Pacific, are of evolutionary 
significance because they are the most primitive living members of their lineages, the 
pedunculate Scalpellomorpha and sessile Verrucomorpha (Fig. 4A-1 and C-1, respec- 
tively). It is also biogeographically significant that these two ancient "Mesozoic" mor- 
phologies are found today as relics in the refugium provided by abyssal hydrothermal 
springs. Thus, the discovery of Neoverruca not only further falsifies the hypothesis that 
the Brachylepadomorpha and Verrucomorpha rose independently from scalpellomor- 
phan ancestors (see Newman 1987), it further falsifies the hypothesis that vents and 
cognate environments are inhabited by rapidly evolving recent immigrants (see New- 
man 1985). 

Neoverruca, in having a verrucomorphan facies superimposed on a brachylepa- 
domorphan ground plan, represents a "missing link" as well as a "living fossil" relevant 
to the early evolution of the sessile barnacles. Neoverruca is furthermore remarkable 



269 




Figure 5. Geological ranges of the principal sessile barnacles and their ancestral pedunculate lineage. 
Of the three lineages of sessile barnacles, (1) all appear in the Cretaceous; (2) the earliest, the Brachylepa- 
domorpha, went extinct, but its organization plan was central to the evolution of the higher forms; (3) the 
Verrucomorpha, including the most primitive living sessile barnacle, Neovernica, is moderately diverse 
although presently confined almost exclusively to the deep sea; and (4), the Balanomorpha, including the 
oldest surviving members Catophragmus s. 1. and Chionelasmus, having a relict intertidal distribution and 
a moderately deep-water Indo-West Pacific relic distribution, respectively, has a substantial diversity pri- 
marily in shallow water (Newman and Stanley 1981). 

Solid vertical bars represent the ranges of genera; the gap in the bar under Catophragmus s. 1. probably 
reflects the fact that intertidal Balanomorpha are less frequently encountered in the fossil record than are 
shallow-water forms. However, the Cretaceous form appears only remotely related to the Recent forms which, 
in themselves, represent three morphologically very distinct and geographically isolated populations (Stanley 
and Newman 1980). The dashed vertical lines indicate inferred ranges, and the extensive range for Neolepas, 
initially justified on theoretical grounds, has been corroborated by a tentative identification of its morphology 
in the Triassic of New Caledonia (Buckeridge and Grant-Mackie 1985). While the thoracican cirripeds may 
stem from the Cambrian (Collins and Rudkin 1981; but see Briggs 1983), the oldest potential relatives of 
the scalpellomorphan pedunculates are the Carboniferous praelepadids and, therefore, the dashed arrow 
directed toward the earliest Mesozoic scalpellomorphs can be inferred to stem from them (Newman et al. 
1969, Newman 1987). 



in passing through a number of pedunculate juvenile stages during ontogeny. Therefore, 
knowledge of Neoverruca provides insights not only into the affinities between sym- 
metrical and asymmetrical sessile barnacles, but into their pedunculate ancestors as 
well, and then beyond what analyses of extant pedunculate barnacles have been able 
to provide. 

The origin of symmetrical sessile barnacles.— A.s Darwin (1854) noted, the sym- 
metrical sessile barnacles differ from their ancestral scalpellomorphan prototype in a 
number of features, the most obvious being the conversion of the peduncle into a flat, 
membranous basis extending across the perimeter of the capitulum and cementing it 
to the substratum. Other more or less concomitant advances included (1) specialization 
of two or more pairs of latera in closing the gap on each side between the rostrum and 
carina and, ultimately, their complete integration into the wall in higher forms, (2) 



270 

development of a distinctly separate, movable operculum and its subsequent special- 
izations, (3) eventual elimination of the remaining, undedicated basal imbricating plates 
and, finally, (4) reduction of the number of latera making up the primary wall (Fig. 4B, 
D-1-3). 

There also were a number of changes within the mantle cavity in the course of 
evolution from the pedunculate to the symmetrical mode. Two important ones involved 
the loss of the ovigerous fraena, setose devices holding the eggs in place, and the loss 
of filamentary appendages, strap-like organs presumably used in respiration. Filamen- 
tary appendages were replaced by branchiae in balanomorphs (Darwin 1 854) and, while 
higher balanomorphs have branchiae alone, Walker (1983) discovered that the primitive 
balanomorph Catophragmus has both fraena and branchiae. On the other hand, while 
higher verrucomorphans were presumed to have lost fraena and filamentary append- 
ages, they apparently never developed branchiae. It is noteworthy that Neoverruca, the 
first sessile barnacle known to have ovigerous fraena and a filamentary appendage, 
satisfies this expectation; in fact, this must also have been the condition in brachyle- 
padomorphans because it is the condition in some surviving members of the pedun- 
culate lineage that gave rise to them. 

Catophragmus (Fig. 4D-2) was the most primitive sessile barnacle known to Dar- 
win (1854), and he treated it as a model elucidating transitional features between 
pedunculate barnacles like Pollicipes and Capitulum and the higher sessile barnacles. 
Subsequently, two extinct sessile barnacles (Brachylepas Woodward, 1901, and the 
somewhat more primitive Pycnolepas Withers, 1914Z); see Fig. 4B herein) replaced 
Catophragmus as the most primitive forms. However, despite Woodward's and With- 
ers' considerations to the contrary, Pilsbry (1907) pronounced that the arrangement of 
imbricating plates in the Brachylepas and Catophragmus was basically different and 
that the two lineages had likely arisen independently from pedunculate ancestors. How- 
ever, a recent study of the imbricating system in Brachylepas cretacea {see Newman 
1987), including an analysis of the principal latera as viewed from within as well as 
from without, revealed how the arrangement of latera seen in balanomorphs could 
have been attained through loss and rearrangement of certain of the principal latera in 
a Brachylepas-like ancestor. The phylogenetic inferences so derived, including the 
tranfer of the median latus to the operculum in the evolution of Catophragmus, called 
for rejection of polyphyly in favor of monophyly in the evolution of the symmetrical 
sessile barnacles (Newman 1987). Knowledge of the basically brachylepadomorphan 
organization of Neoverruca, and the presence of pedunculate stages in its ontogeny, 
does much to further our understanding of how this transition took place. 

The origin of the asymmetrical sessile barnacles. —Understanding of the origin of 
verrucomorphans has been clouded by conjecture since Darwin (1854). He spent much 
of his time on Verruca s. 1., morphologically the most specialized of the verrucomor- 
phans as we know them today, in working out homologies of the plates with those of 
scalpellomorphan and balanomorphan barnacles and in trying to decide whether the 
unique organization plan (Fig. 4C-3) had pedunculate or sessile antecedents. While 
ambivalent throughout most of his deliberations, Darwin did state that if compelled 
he would with much hesitation place Verruca closer to the sessile than to the pedunculate 
barnacles. 

On the other hand, following the discovery of the first living representative of the 
pedunculate barnacles, Scillaelepas, and the primitive verrucid having two pairs of 
somewhat similarly deployed latera, Proverruca (Fig. 4A-2 and C-2, respectively), Pils- 
bry (1916) accepted a pedunculate origin for the verrucids and proposed a new suborder, 
the Verrucomorpha. Shortly thereafter, it was discovered that fossil material previously 
thought by Darwin and others to represent Pollicipes s. 1. constituted a new sessile 
genus, Pycnolepas, related to but more primitive than Brachylepas. This led to the 
creation of a third independent suborder of sessile barnacles, the Brachylepadomorpha 
(Withers 1923; see Fig. 4B herein) and to the notion of a triphyletic origin of the sessile 
barnacles that became the dogma that all workers followed (Kriiger 1940, Withers 
1953, Newman et al. 1969, Newman and Ross 1976, Newman 1982). However, as 
noted above, compelling evidence for independent pedunculate origins for the Brachy- 



271 



lepadomorpha and Balanomorpha is lacking; to the contrary, by loss and rearrangement 
of the latera it is quite apparent how the latter could have been derived from the former 
(Newman 1987). And now the structure of the new form, Neoverruca, clearly illustrates 
the brachylepadomorphan origin of the Verrucomorpha and falsifies the hypothesis of 
even a diphyletic origin of the sessile barnacles involving these two lineages. 

Neoverruca displays, in a subtle way. the profound initial morphological adjust- 
ments made in the shell of a Brachy/epas-hke ancestor that led to the development of 
the unique wall and operculum of the asymmetrical sessile barnacles. Such adjustments 
are most readily made when the latera involved have not become an integral, dedicated 
part of the primary wall, and their being readily excludable allowed one half of the 
brachylepadomorphan operculum to be incorporated into the primary wall of the 
verrucomorphan. This remarkable adjustment is rendered comprehensible when it is 
noted that it involves the barnacle's leaning to one side or the other during ontogeny. 
The adaptive value of leaning over, in an otherwise relatively high sessile barnacle, 
becomes obvious if the development following settlement of a young barnacle in a 
crowded colony is followed; leaning over allows young individuals to extend their cirri 
upward and outward, in the same direction as those of the adults on which they settled 
(Newman 1989). It is evident that this initially small adjustment, of letting the 
scutum and tergum of one side come down between the rostrum and carina during 
ontogeny, set the stage for the remarkable divergence of the asymmetrical from the 
symmetrical forms early in the evolutionary radiation of the sessile barnacles. 

Finally, it should be noted that while Withers (1914^) considered the latera of 
proverrucids to be the rostro- and carino-latera (RL/CL) of a Scillaelepas-likQ ancestor, 
Newman (1987) concluded they were as likely to be the rostro- and median latera (RL/ 
L). However, we now know that the median latus goes with the operculum in neo- 
verrucids, and therefore it cannot be one of the wall latera in proverrucids. Furthermore, 
from knowledge of the ontogeny of Neoverruca (Newman 1989), it is apparent that 
the evolutionary transition from a neoverrucid to the proverrucid wall must have 
involved progenesis (curtailment of whorl production following the formation of the 
first whorl). Therefore, since it appears ontogenetically and progenetically impossible 
for the latera in proverrucids to be plates from any of the subsequent whorls, they must 
be RL/CL, as Withers had proposed. 

Pedunculate ancestors of the sessile barnacles.— The most primitive living scal- 
pellomorph is the hydrothermal barnacle Neolepas. It has simple capitular armament 
including but one pair of latera (Fig. 4A-1). A more advanced form, Scillaelepas, 
abundant in shallow water in the Cretaceous but presently represented by a dozen or 
so species living only in the deep sea, has added two more pairs of latera, a subcarina, 
and sometimes one or more subrostra (Fig. 4A-2; Newman 1980). More advanced and 
ordinarily intertidal forms, the Tethyan relict Pollicipes and the Indo-West Pacific relic 
Capitulum (Fig. 4A-3), have several additional whorls of smaller latera around the base 
of the capitulum. There has been a long-standing consensus that the sessile barnacles 
evolved from the scalpellomorph lineage represented by these genera (Darwin 1854, 
Woodward 1901; Newman et al. 1969; Ghiselin and Jaffe 1973; Anderson 1983; New- 
man 1982, 1987). The existence and nature of the pedunculate stages in the ontogeny 
of the most primitive living sessile barnacle (Newman 1989), Neoverruca, illustrate 
that the Darwinian/Woodwardian model for the pedunculate ancestry of the sessile 
barnacles is well founded. 

Acknowledgments 

We would like to acknowledge the constructive criticism and advice of two anon- 
ymous referees. 

Addendum 

What is apparently the most primitive living balanomorphan, fitting between B 
and D-1 in Figure 4 herein, has been recently recovered by Japanese scientists from 
an abyssal hydrothermal spring at approximately 2000 m in the North Fiji Basin 
(Toshiyuki Yamaguchi, personal communication). 



272 



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101-llL 




TRANSACTIONS 
OF THE SAN DIEGO 

^S?DV SOCIETY OF 

LIBRAKT NATURAL HISTORY 



MAV 1 6 1989 



n. niPS 



HAH*U)|ume 21 Number 17 pp. 275-282 30 April 1989 

UNIV 

New stratigraphic and geographic occurrences of Isognomon (Mollusca: 
Bivalvia) from the Eocene of California and Oregon 

Richard L. Squires 

Department of Geological Sciences, California State University, Northridge, California 91330, USA 



Abstract. The bivalve Isognomon (Isognomon) clarki (Effinger, 1938), previously only known from the 
upper Eocene part (Galvinian Stage) of the Lincoln Creek Formation of southwestern Washington, is reported 
here from five other Eocene formations. Four are in southern California: the upper Juncal Formation, the 
upper Torrey Sandstone, the basal Tejon Formation, and the Coldwater Sandstone; fifth is the Keasey For- 
mation of northwestern Oregon. Except in the upper Juncal Formation, the presence oi Isognomon specimens 
was previously unrecorded. The geologic age range of this species is extended downward into the middle 
Eocene ("Domengine Stage"). Isognomon (I.) clarki is the only species of its genus known from the Eocene 
of the West Coast, and this study is the first documentation that this genus formed dense populations in 
the Eocene. Most of these populations are in coarse-grained pebbly sandstone sediments that indicate near- 
shore conditions. Rare specimens in the Lincoln Creek and Keasey formations are anomalous because they 
are in deep-water fine-grained sediments. 

Introduction 

The bivalve Isognomon is rare in the fossil record of the West Coast (California, Oregon, and 
Washington). Only two species are known, and their occurrence is very locaHzed. This scarcity is prob- 
ably linked to the high-energy habitat of Isognomon species, which commonly inhabited intertidal 
areas subject to erosion. The earliest West Coast species known is Isognomon (Isognomon) clarki 
(Effinger, 1938) from the Eocene part of the Lincoln Creek Formation of Washington. In addition, 
Isognomon sp. (Clark and Woodford 1927) from the Meganos Formation and Isognomon n. sp.? Givens 
(1974) from the Juncal Formation have been reported from Eocene rocks of California. 

The only West Coast Oligocene species is Isognomon panzana (Loel and Corey, 1932) from the 
upper Oligocene through lower Miocene Vaqueros Formation, California. The cooler conditions that 
predominated from middle Miocene through Recent times are the inferred cause of the elimination 
of Isognomon from the West Coast's higher latitudes. Today in western North America, there are 
only two species of Isognomon, extending north only as far as Baja California, primarily in warm 
lagoons (Keen 1971). 

Four previously unknown stratigraphic occurrences of West Coast Paleogene Isognomon can now 
be added. These are the upper Torrey Sandstone, San Diego County, southern California; the basal 
Tejon Formation, Kern County, south-central California; the Coldwater Sandstone, Ventura County, 
southern California; and the upper Keasey Formation, Columbia County, northwestern Oregon 
(Figure 1). In all these Eocene formations, except the Meganos Formation, I believe the specimens 
represent /. (/.) clarki (Effinger). The Meganos Formation occurrence is not included at this time 
because there is not enough material to allow a conclusive determination. 

Methods 

During field investigations of the Tejon Formation, I collected abundant specimens of Isognomon. 
The other three previously unknown stratigraphic occurrences are based on museum material I iden- 
tified while examining collections in museums. The primary type specimens of /. (/.) clarki and the 
hypotypes from the Juncal Formation were borrowed from museums. 



276 



^45'' 



Type Locality 
Keasy Formation 



^40** 



PACIFIC OCEAN 



35' 



Tejon Formation 
Juncal Formation • 



Coldwater Sandstone 



30" 



200 400 600 800 km 

L 1 1 1 1 1 I I I 




Torrey Sandstone — A* 



120 



Figure 1. Stratigraphic occurrences of Isognomon (Isognomon) clarki (Effinger, 1938). 



277 



Observations on the height of the Hgamental area and number of Hgamental grooves of modern 
Isognomon were made on specimens in the malacological collections of the San Diego Society of 
Natural History. 

The usage of molluscan provincial Eocene stages for California is based on Clark and Yokes (1936) 
with modifications by Givens (1974). The ages of these stages follow Saul (1983) and Squires (1984, 
1987). The usage and ages of molluscan Eocene stages for northwestern Oregon and Washington follow 
Armentrout (1975, 1981). 

Abbreviations used for catalog and/or locality numbers are CSUN, California State University, 
Northridge; LACMIP, Natural History Museum of Los Angeles County, Invertebrate Paleontology 
Section; SDSNH, San Diego Society of Natural History; UCR, University of Cahfornia, Riverside; 
UCMP, University of Cahfornia Museum of Paleontology, Berkeley. 

Stratigraphic Occurrences 

Type Locality.— Effinger (1938) named and reported Isognomon (Isognomon) clarki [= F^dalion 
clarki] from the Gries Ranch beds, just east of Vader, Lewis County, southwestern Washington. Only 
two valves were found, at locality UCMP 3607. Mainly on the basis of the abundance of sessile near- 
shore invertebrates, he interpreted the environment to have been nearshore or littoral. C. S. Hickman 
(personal communication, 1988), however, believes the shallow-water invertebrates were transported 
into a deep-water environment. Durham (1944:112, fig. 7) assigned the Gries Ranch beds to his 
Molopophorus stephensoni megafaunal Zone. Armentrout (1975) assigned the M. stephensoni Zone 
to the Echinophoria dalli Zone in the lower part of the Lincoln Creek Formation and in the middle 
of his Galvinian Molluscan Stage of late Eocene age. 

California. — Givens (1974) reported the first occurrence of Isognomon from the Eocene of Cali- 
fornia. His specimens were from the upper half of the Juncal Formation, Pine Mountain area, Ventura 
County, southern California, at a single locality (UCR 4752) in a lens of calcareous sandy conglomerate. 
He identifed these specimens as Isognomon n. sp.? pending the discovery of more complete material. 
Givens' material consists of three large (up to 14 cm in height) articulated and two fragmentary 
specimens. From the presence of Isognomon and associated moUusks he interpreted this Isognomon- 
bearing bed as having formed in a shallow-water (inner sublittoral) environment at the seaward margin 
of a delta. The bed lies within the Tiirritella uvasana applinae fauna of the Juncal Formation, and 
this fauna is equivalent to the West Coast megainvertebrate provincial middle Eocene "Domengine 
Stage." 

The new stratigraphic occurrence of /. (/.) clarki in the Torrey Sandstone is near the top of the 
formation, east of the city of Del Mar, in a new development called North City West, San Diego 
County, southern California. A 20-m-thick section of the Torrey was exposed in 1985 by bulldozing 
during construction. A 15-m-thick section of Ardath Shale was also exposed. The contact between 
the two units was sharp, and locally the claystone of the Ardath draped over cobbles at the top of 
the Torrey Sandstone. Overlying the Ardath was 10 m of the Scripps Formation. A housing tract now 
covers most of the entire section. 

Specimens of /. (/.) clarki were found near the top of the 20-m-thick section of the Torrey Sand- 
stone. The collecting site was a 30- to 60-cm-thick pebbly sandstone bed at locality SDSNH 3282. 
Thirty-three specimens were collected, of which 15 were right valves and 17 were left valves. Only 
a single articulated specimen was found. Most of the specimens are fragmentary, but preservation 
of the shell material is excellent. Only one complete left valve 12.5 cm in height (hypotype SDSHN 
35235) (Figures 2.1, 2.2) was found. No complete right valves were found, but the best example is 
hypotype SDSNH 35236 (Figures 2.3, 2.4). 

Mollusks in the Torrey Sandstone are rare. Previously, only two species were reported by Givens 
and Kennedy (1979:85). Associated shallow-water mollusks at locahty 3282, however, are common. 
Other taxa include a solitary coral, a bryozoan, a brachiopod, barnacle fragments, a brachyuran, 
four shark species, a ray, a turtle, a glyptosaurine lizard, and a rodent (T. A. Demere, personal com- 
munication, 1988). 

A nearshore environment for locality 3282 is indicated by the mixing of marine and nonmarine 
fauna. According to Givens and Kennedy (1979), a middle Eocene age ("Domengine Stage") for the 
Torrey Sandstone is indicated by that formation's interdigitating with the lower part of the more readily 
dated middle Eocene Ardath Shale. 



278 




Figure 2. Isognomon (Isognomon) clarki (Effinger, 1938), middle Eocene ("Domengine Stage") upper Torrey Sand- 
stone, locality SDSNH 3282. 1-2, SDSNH hypotype 35235, left valve, xO.6, height 12.5 cm, width 10.8 cm. 1, 
exterior. 2, interior. 3-4, SDSNH hypotype 35236, partial right valve, xO.7, height 9 cm, width 9.7 cm. 3, exterior. 
4, interior. 



The new stratigraphic occurrence of /. (/.) clarki in the Tejon Formation is in the basal part of 
the formation, Tehachapi Mountains, Kern County, south-central California. This part of the for- 
mation is rarely exposed because it is normally covered by extensive landslides and/or slope wash. 
A road cut made in 1971 along the east side of the Edmonston Pumping Plant, however, exposed 
a 122-m-thick section. The lowest 27 m consists of shoreline-associated deposits laid down as a trans- 
gressing sea advanced over an irregular surface of gneissic bedrock. Channel-lag storm accumula- 
tions of oyster hash and other mollusks indicate a rocky nearshore environment (Squires 1989). 

At locality CSUN 1201, 13 m above the base of the section, numerous Isognomon valves (up to 
9 cm in height) were found in closely packed layers. TXventy-four specimens were collected, three of 
which are articulated and range in height from 6 to 8 cm. They indicate that the distance of post- 
mortem transport was short. The other specimens consist of six right valves and 12 left valves, all 



279 



poorly preserved and consisting of only partial shells (chalky) or internal molds. Above 27 m, mollusk- 
bearing channels are scarcer, and mollusks indicating subtidal environment increase (Squires 1989). 
Single fragmentary specimens of /. (/.) clarki were found at localities CSUN 1202 and 1203, 19 and 
63 m, respectively, above the base. 

Nilsen (1987:90-92, fig. 58) listed mollusk species from a few beds in the Edmonston Pumping 
Plant section and diagrammed the section. Isognomon was not Usted; neither was it found by early 
workers (Gabb 1864; Dickerson 1915, 1916; Anderson and Hanna 1925) who described molluscan 
faunas from the Tejon Formation in the Tehachapi Mountains and the adjacent San Emigdio 
Mountains. 

The lower 63 m of the Edmonston Pumping Plant section is of middle Eocene age ("Transition 
Stage"), as indicated by the overlapping of Turritella uvasana uvasana and Ficopsis remondii crescentensis. 
The remaining 59 m is of middle Eocene age ("Tejon Stage"), as indicated by the presence of Tur- 
ritella uvasana sargeanti (Squires 1989). 

The new stratigraphic occurrence of/. (/.) clarki in the Coldwater Sandstone, upper Sespe Creek, 
Ventura County, southern Cahfornia, is at locality CSUN 252. The formation in this area has received 
very little geologic study. Four large (up to 12 cm in height) articulated specimens were found in well- 
sorted fine-grained sandstone. Associated mollusks include abundant very large (up to 18 cm in height) 
articulated oysters and a few articulated Venericardia sp. Sturdy-shelled oysters and Venericardia remain- 
ing in situ indicates nearshore shallow water. The well-sorted nature of the sandstone supports this 
interpretation and suggests a sand-bar environment. 

Oregon. — ^The new stratigraphic occurrence of /. (/.) clarki in the Keasey Formation is in the upper 
part of the middle member of the formation at the Smithwick Haydite quarry, south of Vernonia, 
Columbia County, northwestern Oregon. An articulated partial specimen was found in siltstone at 
locality LACMIP 5806. C. S. Hickman {personal communication, 1988) collected two additional 
specimens from this quarry. Both are articulated and one is complete. Hickman (1976) interpreted 
the environment of the Keasey Formation to be bathyal. The articulated specimen of Isognomon is 
anomalous in this deep-water assemblage. Isognomon today may attach itself to roots of mangrove 
trees (Emerson and Jacobson 1976). Its occurrence in the Keasey may have resulted from individuals 
being attached to floating wood that eventually sank in deep water. 

The Keasey Formation is of late Eocene age (Hickman 1976, 1980; Armentrout et al. 1983). The 
/. (/.) clarki specimen from locality LACMIP 5806, therefore, is of the same geologic age as those 
from the type locality found by Effinger (1938). 

Systematic Paleontology 

Class Bivalvia Linne, 1758 

Subclass Pteriomorphia Beurlen, 1944 

Order Pterioida Newell, 1965 

Suborder Pteriina Newell, 1965 

Super family Pteriacea Gray, 1847 

Family Isognomonidae Woodring, 1925 

Genus Isognomon Solander in Lightfoot, 1786 

Type Species. — By monotypy, Ostrea perna Linne, 1767, Recent, Indo-Pacific. 

Subgenus Isognomon s.s. 

Isognomon {Isognomon) clarki Effinger, 1938 

Figure 2.1-2.4 

Pedalion clarki Effinger, 1938:367-368, pi. 45, figs. 9-10. Weaver, 1943:77, pi. 13, fig. 9. 

Isognomon n. sp.? Givens, 1974:43-44, pi. 2, fig. 6. 

Isognomon {Isognomon) n. sp.? Givens. Moore, 1983:85, pi. 26, fig. 1. 

The Torrey Sandstone specimens are better preserved than the primary type specimens, warrant- 
ing the following supplementary description: equivalved, inequilateral, subquadrate, moderately 
inflated, and large (up to 14 cm in height); prosogyrate beaks somewhat extended anteriorly; anterior 
margin nearly straight, becoming concave near beak and reflected and forming a ridge in byssal gape 
area below beak, reflection more pronounced on left valve; angle between hinge line and anterior 



280 



margin about 65°; posterior and ventral margins evenly rounded; hinge line straight with up to 21 
ligamental grooves that are about half as wide as the interspaces, posteriorly the interspaces become 
wider; ligamental area flat and broad to very broad, depending on the particular specimen; very narrow 
byssal gape below beaks; pallial line near anterior margin marked by small nodes and pits; shell surface 
with closely spaced growth Hnes; holotype height 12.5 cm, length 11 cm, (h/l = 1.14), width of both 
valves together 3 cm. 

Discussion .—The use of the subgenus Isognomon in this present report follows Cox (1969). 

All the West Coast Eocene isognomonid specimens are judged to be /. (/.) clarki because they 
are morphologically inseparable. The only differences are minor and fall within Umits of normal varia- 
tion seen in comparably sized modern species oi Isognomon. The two adult specimens of/. (/.) clarlii 
shown in Figure 2 differ in the height of the ligamental area and number of hgamental grooves. This 
kind of variation is also present in adult specimens of /. recognitus from Kino Bay, Sonora, Mexico, 
with a few specimens having ligamental area heights 25 percent greater than that of the average 
specimen. Similary, the height of the ligamental area in adult specimens of/, isognomum from Manila, 
PhiUppine Islands, varies from specimen to specimen, with a few specimens having heights 50 percent 
greater than the average. In addition, there are 19 ligamental grooves in young adults versus 23 ligamental 
grooves in mature adult specimens of this species. 

The specimen shown in Figures 2.1 and 2.2 is the widest known specimen of / (/) clarki because 
it is the most complete specimen of this species. 

Isognomon (I.) clarki is most similar to Isognomon (/) panzana (Loel and Corey, 1932:187, pi. 
9, figs, la-b, 2-6) from the upper Oligocene and Miocene Vaqueros Formation, California. Moore 
(1983:84, pi. 25, figs. 3 and 6) also figured this species. Isognomon (/) clarki differs from / {I.) panzana 
in the following features: much wider, h/l = 1.1 rather than 1.8, angle between hinge line and anterior 
margin about 65° rather than about 75°, 12 rather than 9 ligamental grooves in specimens about 9 
cm high, irregular divaricate-radial plications on the exterior absent, and posterior ventral margin 
not crenulate. 

A specimen from the lower Eocene Meganos Formation of north-central CaUfornia, referred to 
as Pedalion sp. by Clark and Woodford (1927:88, pi. 14, fig. 8), may be an Isognomon and may be 
conspecific with / (/) clarki. Moore (1983:84-85, pi. 26, fig. 3) identified this specimen as Isognomon 
sp. My examination of this tiny (height 12 mm) fragmentary specimen revealed that it does have a 
straight hinge line, but the view is of the exterior and no ligamental grooves can be seen. More mate- 
rial of this species is needed for an identification to genus. 

Material. — Sixty-six specimens. 

Occw/reAZce.— ^'Domengine Stage" through Galvanian Stage, equivalent to the upper lower through 
upper Eocene (upper Ypresian through Priabonian stages of Europe). 

"Domengine Stage": Upper Torrey Sandstone, northern San Diego County, southern California 
(locality SDNHM 3282); upper Juncal Formation, Turritella uvasana applinae fauna, Pine Mountain 
area, Ventura County, southern CaUfornia (locality UCR 4752). 

"Transition Stage": Lower Tejon Formation, Kern County, south-central Cahfornia (localities CSUN 
1201, 1202, 1203). 

"Tejon Stage": Coldwater Sandstone, upper Sespe Creek, southern Cahfornia (locality CSUN 252). 

Galvanian Stage (equivalent to the "Tejon Stage"): Upper part of the middle member of the Keasey 
Formation, Smithwick Haydite quarry, Columbia County, northwestern Oregon, (locality LACMIP 
5806); lower Lincoln Creek Formation, near Vader, Lewis County, southwestern Washington (locality 
UCMP 3607). 

Repositories.— Holotype, UCMP 33513. Paratype, UCMP 33514. Hypotypes, UCR 4752/61; 
SDSNH 35235 and 35236. 

Acknowledgments 

T. A. Demere, San Diego Natural History Museum, D. R. Lindberg and L. Bryant, University 
of California, Berkeley, M. A. Kooser, University of Cahfornia, Riverside, and E. C. Wilson, Natural 
History Museum of Los Angeles County, provided loans. T. A. Demere also provided a macro faunal 
hst for locality SDSNH 3282. B. O. Riney, San Diego Natural History Museum, found the Torrey 
Sandstone specimens and kindly gave detailed locality information. M. A. Roeder, San Diego Natural 
History Museum, screened sediment from locaUty SDSNH 3282 and sorted out the vertebrate material. 



281 



A. E. Fritsche, California State University, Northridge, found the Coldwater Sandstone specimens. 
C. S. Hickman, University of California, Berkeley, showed me additional specimens of Isognomon 
from the Keasey Formation. 

C. L. Powell, II, U.S. Geological Survey, Menlo Park, arranged loans of mollusks associated with 
the Isognomon from the basal Tejon Formation. R. C. Brusca, San Diego Natural History Museum, 
allowed access to the malacological collections. 

Al Grmela, Department of Water Resources, Bakersfield, granted permission to enter and collect 
specimens at the Edmonston Pumping Plant. Mildred Wiebe, Tejon Ranch, granted permission for 
paleontologic investigations on the Tejon Ranch area west of the Edmonston Pumping Plant. 

The manuscript benefited from comments by two anonymous reviewers. California State Univer- 
sity, Northridge, kindly funded page changes. 



Localities 

All the quadrangle maps listed below are 7.5-minute, unless otherwise specified. 

CSUN 252. Just north of upper Sespe Creek, NW 1/4, SW 1/4, SW 1/4 of section 35, T 6 N, 
R 22 W, Lion Canyon quadrangle, California (1943). 

CSUN 1201. Roadcut exposure about 20 m east of the eastern side of Edmonston Pumping Plant, 
13 m above base of Tejon Formation, Pastoria Creek quadrangle, California (photorevised 1974). 
Equivalent to U.S. Geological Survey, Menlo Park, Cenozoic collection locality M4631, given in Nilsen 
(1987:90). 

CSUN 1202. Roadcut exposure about 20 m east of the eastern side of Edmonston Pumping Plant, 
19 m above base of Tejon Formation, Pastoria Creek quadrangle, CaUfornia (photorevised 1974). 

CSUN 1203. Roadcut exposure about 60 m N5 E of the northeast corner of Edmonston Pumping 
Plant, 63 m above base of Tejon Formation, Pastoria Creek quadrangle, California (photorevised 
1974). Equivalent to U.S. Geological Survey, Menlo Park, Cenozoic collection locality M4633, given 
in Nilsen (1987:91). 

LACMIP 5806. Smithwick Haydite Quarry, 0.4 km north of the high trestle across Oregon Highway 
47, 13.6 km south of Vernonia, Washington County, Oregon. 

SDNHM 3282. Hillside exposure (now mostly covered), 330 m north and 330 m east of southwest 
corner of section 8, T 14 S, R 3 W, Del Mar quadrangle, California (1967). 

UCMP 3607. In south bank of Cowlitz River at the old Gries Ranch in the NW 1/4 of section 
25, T 11 N, R 2 W, Castle Rock 15-minute quadrangle, Washington (1953). 

UCR 4752. On the crest of a southwest-trending ridge northeast of the main fork of Piru Creek, 
525 m south and 735 m east of the northwest corner of section 29, T 7 N, R 21 W, San Guillermo 
quadrangle, California (1943). 

Literature Cited 



Armentrout, J. M. 1975. Molluscan biostratigraphy 
of the Lincoln Creek Formation, southwest 
Washington. Pp. 14-28 in D. E. Weaver, G. R. 
Hornaday, and A. Tipton (eds.). Future energy 
horizons of the Pacific Coast; Paleogene sym- 
posium and selected technical papers. Pacific 
Section, Society of Economic Paleontologists and 
Mineralogists, Los Angeles. 

Armentrout, J. M. 1981. Correlation and ages of 
Cenozoic chronostratigraphic units in Oregon and 
Washington. Pp. 137-148 in J. M. Armentrout 
(ed.). Pacific Northwest Cenozoic biostratigraphy. 
Geological Society of America Special Paper 184. 

Armentrout, J. M., D. A. Hull, J. D. Beaulieu, and 
W. W. Rau. 1983. Correlation of Cenozoic 
stratigraphic units of western Oregon and 
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IVIQ2 TRANSACTIONS 

LIBRARY OF THE SAN DIEGO 

SOCIETY OF 
JAN 2 9 1990 NATURAL HISTORY 

HARVARD 
UNIVERSITY 

Volume 21 Number 1 8 pp. 283-290 1 5 October 1 989 



Homology and terminology of higher teleost postcleithral elements 

Michael D. Gottfried 

Museum of Natural History and Department of Systematics and Ecoloi^y, Dyche Hall, University of Kansas. Lawrence, 
Kansas 66045-2454: Field Associate. San Diego Natural History Museum. P.O. Bo.x 1390. San Dici^o. California 
92112. USA 

Abstract. Primitively, actinopterygians have a single postcleithrum, which is not homologous to the 
anocleithrum of sarcopterygians. The possession of multiple postcleithra is a shared derived feature of leleosts. 
Three to five postcleithra are typically found in lower teleosts; as many as seven are present in primitive fossil 
forms. Consideration of the positional relationships of postcleithra in primitive teleosts provides criteria for 
homoiogizing and naming teleost postcleithra. Ctenosquamate teleosts (myctophiforms and acanthomorphs) 
typically possess two postcleithra; on the basis of positional relationships these are interpreted as postcleithra two 
and three (not "one and two," "upper and lower," "dorsal and ventral," or "proximal and distal" as in previous 
interpretations). Ctenosquamates are therefore derived in having lost postcleithrum one. which is considered here 
to be the homologue of the single postcleithrum of primitive actinopterygians. 

Introduction 

The postcleithral elements of actinopterygian fishes are small dermal bones that lie along 
the posterior border of the pectoral girdle. Primitively, actinopterygians have a single, 
relatively small postcleithrum located at and extending dorsal to the juncture between the 
supracleithrum and cleithrum and lying medial to those two bones. This single postcleithrum 
can be seen in the Devonian genus Cheirolepis (Pearson and Westoll 1979), which is the most 
primitive actinopterygian according to recent analyses (Lauder and Liem 1983. Gardiner 
1984). It is also present in the following lower actinopterygian groups: Cladistia [Polypterus, 
Jollie 1984b), Chondrostei {Polyodon, Gregory 1933), Ginglymodi {Lepisosteus, Jollie 1984a), 
and Halecomorphi {Amia, Figure 1 A); the last is the sister taxon of the Teleostei (Schultze and 
Wiley 1984). 

Extant lower teleosts typically have three postcleithra (Gosline 1980). with the most 
dorsal occupying the same relative position as the single postcleithrum of lower 
actinopterygians and the additional postcleithra a more ventral position. As many as six 
(possibly seven) postcleithra have been described by Arratia (1984, 1987) in the unusual 
Jurassic teleost Vavasichthys, while five are known in several other Jurassic forms including 
Bohhichthys, Protoclupea, and Domeykos (Arratia 1987) and in juvenile Salmi) (Arratia and 
Schultze 1987). Five postcleithra are also found in extant Elops (Figure IB); Gosline (1980) 
referred to the two most ventral postcleithral elements in Elops as axillary scales, but Arratia 
(1984) considered them to be true postcleithra on the basis of their structure and lack of scale- 
like ornamentation. 

While the exact number of postcleithra primitive for teleosts is not certain (because of 
poor phylogenetic resolution at the base of the Teleostei). and reduction in number or complete 
loss of postcleithra has occurred within different teleost groups (Gosline 1980). it is most 
parsimonious to hypothesize multiple postcleithra (probably five) as a teleost synapomorphy. 

The ctenosquamate teleosts (myctophiforms and acanthomorphs; Rosen 1973) 
characteristically possess two postcleithra. The intent of this paper is to provide positional and 
phylogenetic criteria for homoiogizing teleost postcleithra and to detennine which elements are 
represented in ctenosquamates. 



284 




Figure 1. A, lateral view of the pectoral girdle in a lower actinopterygian, Amia calva, KU 1798 (note single 
postcleithruin positioned at supracleithrum/cleithrum juncture). B, lateral view of the pectoral girdle of a primitive 
teleost, Elops saiinis (note multiple postcleithra); after Arratia and Schultze (1987). Scale bars = 5 mm. Abbreviations: 
cl, cleithrum: pel, postcleithrum; scl, supracleithrum. Numbers 2-5 in B indicate postcleithra 2-5. 



POSTCLEITHRAL TERMINOLOGY 

The multiple postcleithra of teleosts have been subjected to a variety of different 
terminologies based on their relative positions, have been referred to as a "postcleithrum plus 
postpectorals" (Jollie 1986), or have been numbered. The numbering approach is preferable for 
three reasons: it allows for reference to multiple postcleithra without resort to awkward names 
(e. g., the "upper middle postcleithrum" or "middle ventral postcleithrum"), it permits a less 
ambiguous terminology that facilitates comparisons between the postcleithra of different 
forms, and it avoids using another name (the "postpectorals" of Jollie) for elements that in the 
past have consistently been called postcleithra. 

The following positional relationships and suggested terminology are based on the 
location of the postcleithral elements in primitive teleosts such as the Jurassic forms discussed 
by Arratia (1987) and extant Elops (Figure IB). The most dorsal postcleithrum in teleosts, 
which is interpreted here as homologous to the single postcleithrum of lower actinopterygians, 
is most appropriately referred to as postcleithrum 1. It lies at the level of and extends dorsal to 
the juncture between the supracleithrum and cleithrum and, depending on the taxon, extends 
ventrally to a variable degree. It is usually overlapped by a portion of the cleithrum and the 
most ventral part of the supracleithrum. Postcleithrum 2 articulates dorsally with the 
ventromedial margin of postcleithrum 1 and lies at approximately the level of the middle 
region of the cleithrum, medial to the scapula and coracoid. It does not extend as far dorsally as 
the juncture between the cleithrum and supracleithrum. In some forms a gap separates 
postcleithra 1 and 2 (Gosline 1980). Postcleithrum 3 characteristically forms a slender spinous 
process that angles posteroventrally, medial to the pectoral fin. Its somewhat stouter dorsal 
portion articulates with the anteromedial surface of postcleithrum 2. Postcleithrum 3 is a useful 
landmark element and can generally be distinguished by its spinelike appearance and 
posteroventrally angled orientation; in contrast, the other postcleithral elements are more 
flattened and scalelike and often have a crenulated surface . 

Postcleithra 4 through 6 (or 7) form an additional series of sequentially overlapping 
elements that extend back from the lower posterior corner of the cleithrum, lateral to 
postcleithra 2 and 3. Postcleithra 4 and 5 are found in Elops {Figure IB), in juvenile Salmo 



285 

(Arratia and Schullze 1987). and in several Jurassic forms discussed by Arraiia (1987); as 
many as six (possibly seven) are known only in the Jurassic genus Varasichtliys. 

Results and Discussion 

As noted above, ctenosquamate teleosts generally possess two postcleithral elements. 
Exceptions to this exist; e. g., among acanthomorph ctenosquamates some gobioids may lack 
either of the two elements or lack postcleithra entirely (Springer 1983). and some acanthurids 
have only a single postcleithrum (Johnson and Washington 1987). Previous literature shows 
that there has been confusion and a lack of consistency as to which postcleithra these are and 
what they should be called. Some authors (Patterson 1964. Zehren 1979, both referring to 
beryciforms; Springer 1983. referring to gobioids) call these two bones the "dorsal and 
ventral" postcleithra. while others refer to them as "upper and lower" postcleithra (Rosen and 
Patterson 1969, referring to "paracanthopterygians"), "postcleithra 1 and 2" (e. g.. Greenwood 
1976, 1985, Braga and Azpelicueta 1982, Arratia 1982, Kong 1985, all referring to various 
acanthopterygians), or "proximal and distal" postcleithra (KuUander 1988, referring to 
cichlids). 

Examination of the pectoral girdle in a variety of acanthomorph ctenosquamates (see 
"Materials Examined" and Figure 2) confirms that two postcleithra are typical in the group, as 
noted by Gosline (1980). In addition, non-acanthomorph ctenosquamates typically have two 
postcleithra; these include Polymixia (Zehren 1979), the sister taxon of the Acanthomorpha 
according to Rosen (1985) and Stiassny (1986), and myctophiforms (Goody 1969, Paxton 
1972), the sister group oi Polymixia plus the Acanthomorpha (Rosen 1985, Stiassny 1986). 

The two postcleithra in the various ctenosquamates generally occupy the same relative 
positions and have comparable proportions. The more dorsal of the elements is flattened and 
platelike, lies at approximately the level of the middle region of the cleithrum (and medial to 
the scapula and coracoid), is overlapped (to varying degrees) by the cleithrum, and does not lie 
as far dorsally as the most dorsal postcleithrum in primitive teleosts. The more ventral element 
is generally narrower, posteroventrally directed, medial to the pectoral fin, and terminates in a 
pointed process. It articulates dorsally with the anteromedial surface of the postcleithrum 
above it. In some forms, for example. Prionotus (Triglidae. Percomorpha) and Coitus 
(Cottidae. Percomorpha; Figure 2C). the more dorsal postcleithrum is also relatively narrow 
and spinelike. 

The positional relationships described earlier indicate that the two postcleithral elements 
in ctenosquamates are best interpreted as postcleithra 2 and 3. This means that the other 
terminologies are unneccessarily imprecise. More important, it follows from this interpretation 
that postcleithrum 1 (the teleost homologue of the single postcleithrum of lower 
actinopterygians) has been lost in ctenosquamates. and the "postcleithra 1 and 2" terminology 
is therefore inappropriate for the group. 

Although the determination of the elements in ctenosquamates as postcleithra 2 and 3 is 
relatively straightforward, it is neccessary to add one cautionary note. I observed ontogenetic 
fusion in the postcleithra of a cleared and stained series (// = 17) of Cichlasoma citrinellum 
(Percomorpha. Cichlidae); specimens ranged from small juveniles to large adults (35 mm to 
145 mm total length). Juveniles and sub-adults of C. citrinellum have two distinctly separate 
postcleithral elements up to approximately 70-90 mm in total length (Figure 3A). The more 
dorsal of these (postcleithrum 2) is flattened and has a semikmale shape. A thickened spinelike 
ridge runs along the anterior edge of the element, terminating dorsally in a sharp point. 
Posterior to the ridge the bone is thin and has a crenulated surface similar to that of elements in 
the opercular series. The ventrally positioned element (postcleithrum 3) is more robust and 
tapers ventrally to a sharp point. The two bones articulate by means of a shallow depression on 
the dorsolateral surface of postcleithrum 3 into which fits the rounded lower corner of 
postcleithrum 2. 

In contrast, adults of C. citrinellum have what appears to be a single postcleithrum 
(Figure 3B). In these larger fish, the anteriorly positioned ridge of postcleithrum 2 has grown 
down onto postcleithrum 3. and there is no longer any indication of an articulation or that the 



286 




pel 2 



pel 3 






pel 2 



pel 3 



Figure 2. Lateral views of the pectoral girdles of ctenosquamate teleosts. A, Percopsis omiscomaycus, KU 11337 
("Paracanthopterygii," Percopsiformes, Percopsidae). B, Gooclea atripinnis, KU 16998 (Acanthopterygii, 
Atherinomorpha, Atherinidae). C, Cottus hairdi. KU 17151: note reduced pel 2 (Acanthopterygii, Percomorpha, 
Cottidae). D, Lepomis gihhosus, KU 13983 (Acanthopterygii, Percomorpha, Centrarchidae). Scale bars = 2 mm. 
Abbreviations: cl, cleithrum; co, coracoid; pel 2, 3, postcleithrum 2, 3; ra, pectoral fin radials: sc, scapula: scl, 
supracleithrum. 



two elements were once separate. Similar ontogenetic fusion of postcleithra 2 and 3 has been 
observed in the acanthuroid percomorph Zanclus cornutus (Johnson and Washington 1987). 

The most parsimonious interpretation of the loss of postcleithrum 1 in ctenosquamates is 
that it represents an additional synapomorphy corroborating monophyly of the group [see 
Lauder and Liem (1983) and Stiassny (1986) for additional ctenosquamate synapomorphies]. 



287 




pel 2 




2+3 



Figure 3. Left lateral views of postcleithra (pel) of Cichlusoina cifriiie/liiin (Acanthopterygii, Pereomorpha. 
Cichlidae). A, from a juvenile (37 mm total length) in which pel 2 and 3 are separate (KU 21916). B. from an adult 
(118 mm total length) in which pel 2 and 3 are fused (KU 21915). Scale bars = 1 mm. 



The primitive condition relative to that in ctenosquamates is possession of postcleithra 1. 2, 
and 3. Postcleithra 1 through 3 are present in close ctenosquamate outgroups, including the 
order Aulopiformes (Sulak 1977, Gosline 1980), which is the sister group of the 
ctenosquamates according to Lauder and Liem (1983), Rosen (1985). and Hartel and Stiassny 
(1986). Sulak (1977) did describe two synodontid aulopiforms (Synodus and 
Trachinocephalus) as having two postcleithra, which occupy the positions of postcleithra 2 and 
3 by my interpretation. However, Sulak (1977, p. 68) suggested that three postcleithra are 
typical for the group, and basal aulopiforms (e. g., Aidopus) have three postcleithra, so the loss 
of a postcleithrum in some aulopiforms can be interpreted as independent of the loss in 
ctenosquamates. Postcleithra 1 through 3 are also present in further outgroups, including 
salmoniforms, clupeomorphs (Gosline 1980), and characiforms (c. c.. Brxcon. Weitzman 
1962). 

Mapping postcleithral conditions on to an existing hypothesis of actinopterygian 
interrelationships (Figure 4) indicates that the interpretation here is consistent with the 
phylogenetic concept of homology as discussed by Ax (1987). Remane (1952) considered a 
positional relationship such as I have used to be the strongest criterion for establishing 
homology. 

Gosline (1980) interpreted the most dorsal postcleithrum of lower teleosts and the single 
postcleithrum of lower actinopterygians as homologues of the anocleilhrum of sarcopterygians 
(lungfishes, coelacanths, and crossopterygians). I agree with Gardiner (1984) that the single 
postcleithrum of lower actinopterygians should not be considered homologous to the 
anocleithrum. the possession of which has been interpreted as a sarcopterygian synapomorphy 



288 



Actinopterygii 




anocleithnim 



Figure 4. Phylogenetic diagram of the major groups of actinopterygians, with postcleithral conditions specified at the 
appropriate levels. A, single postcleithrum present at juncture of supracleithrum and cleithrum (the primitive 
actinopterygian condition): B, multiple postcleithra (1 through 5), hypothesized here as a teleost synapomorphy, with 
postcleithrum 1 the homologue of the single postcleithrum of lower actinopterygians and 2-5 in a more ventral 
position; C, reduction to postcleithra 1-3: D, reduction to postcleithra 2-3, with loss of postcleithrum 1 interpreted as a 
ctenosquamate synapomorphy; X, independent reduction to a single postcleithrum in the Osteoglossomorpha. ?, 
primitive condition unknown for the Osteichthyes (Actinopterygii plus Sarcopterygii); 0. postcleithra absent. Lower 
right, postcleithra present at the stem of each indicated node within the Actinopterygii. Note presence of anocleithrum 
(here considered nonhomologous to postcleithrum 1) in Sarcopterygii. t. taxa represented by fossils only. Sequence of 
taxa primarily based on Lauder and Liem (1983) and Arratia (in press) for the lower teleo.stean groups. 



(Long 1989). In sarcopterygians, the anocleithrum lies fully within the arcade of pectoral girdle 
elements, articulating dorsally with the supracleithrum and ventrally with the cleithrum and 
preventing those two elements from contacting one another. In the most primitve 
actinopterygians, Cheirolepis (Pearson and Westoll 1979) and Cladistia (Jollie 1984b), the 
postcleithrum has a different position; it lies along the posterior edge of the pectoral girdle, 
where it is overlapped by the supracleithrum and cleithrum, which are in contact. The 
distinction between the anocleithrum and postcleithrum is further clarified by Jollie's (1984a) 
observations on the developmental osteology of the extant ginglymodian Lepisosteus, in which 
the postcleithrum (in juveniles) first forms as a dermal ossification separate from and posterior 
to the pectoral girdle and only later in development contacts and is overlapped by (but does not 
separate) the supracleithrum and cleithrum. The primitive condition for the Osteichthyes 
(Actinopterygii plus Sarcopterygii) is not known because of lack of information on the 
osteichthyan sister group, the Acanthodii (Figure 4). 

Finally, teleost groups other than ctenosquamates reduce the number of postcleithra. 
Siluriforms, mormyrids, anguillids, and engraulids lack postcleithra entirely (Gosline 1980); 
most osteoglossomorphs (Taverne 1977, 1978) and some cyprinids (Gosline 1980) have a 
single postcleithrum. These reductions can best be interpreted as independent losses within 
each lineage. 



289 

Materials Examined 
The following specimens were examined for this study. Except where noted, specimens 
are cleared and stained (for cartilage and bone); they are in the Ichthyology Division of the 
University of Kansas Museum of Natural History (KU). Numbers in parentheses indicate 
number of individuals per lot. 

Actinopterygii, Halecomorphi; 

Amia calva, KU 1798 ( 1; skull only) 
Teleostei, Percopsiformes, Aphredoderidae; 

Aphredoderus sayanits, KU 12390 ( I; cleared only) 
Percopsiformes, Percopsida 

For apsis omiscomaycus, KU 1 1337 (1; in alcohol) 
Gadiformes, Gadidae; 

Microgadus proximus, KU 12150 (I; in alcohol) 
Atherinomorpha, Atherinidae; 

Basilichthys aiistralis. KU 19278 (7) 

Goodea atripinnis, KU 16998 (5) 

Lahidesthes siccidus. K\J 17621 (7) 
Atherinomorpha, Cyprinodontidae; 

Fundulus catenatus, KU 17616 (7) 

Crenichthys halleyi. KU 1 1862 ( 11 ) 
Percomorpha, Percidae; 

Stizostedion canadense, KU 1 7920 ( 1 ) 
Percomorpha, Percichthyidae; 

Morone chrysops, KU 18024 (5) 
Percomorpha, Sciaenidae; 

Aplodinotiis grunniens, KU 21461 (8) 
Percomorpha, Cottidae; 

Cottusbairdi,KV 17151 (7) 
Percomorpha, Triglidae; 

Prionotiis evolans, KU 21435 (2) 
Percomorpha, Centrarchidae; 

Elassoma zonatum, KU 20307 (5) 

MIcropterus salmoides, KU 15939 (2) 

Lepomis gibbosus, KU 13983 (4) 
Percomorpha, Cichlidae; 

Cichlasoma citrinelliim, KU 21915 (1), 21916 (1), 21917 (15) 

Acknowledgments 

I am very grateful to G. Arratia (University of Kansas) for her generous advice and many 
discussions on this topic. F. Cross and J. Collins (University of Kansas) allowed free access to 
the KU fish collections; G. Barlow (University of California, Berkeley) supplied the cichlid 
specimens mentioned in this study. P. Mabee (Smithsonian Institution) and an anonymous 
reviewer provided valuable criticisms and comments. H.-P. Schultze and P. Rasmussen 
(University of Kansas) made helpful suggestions on an earlier version of this paper. Financial 
support was given by the University of Kansas Department of Systematics and Ecology. 

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(London) 204:469-507. 

1986. A primer of bone names for the 



understanding of the actinopterygian head and 

pectoral girdle skeletons. Canadian Journal of 

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Sebastes (Osteichthyes, Scorpaeniformes, 

Scorpaenidae). Estudios Oceanologfa 4:2 1-75. 
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South American rheophilic cichlid fishes with six 

new species. Copeia (1988): 196-230. 
Lauder, G. V, and K. F. Liem. 1983. The evolution 



and interrelationships of the actinopterygian fishes. 

Bulletin Museum of Comparative Zoology 

150:95-197. 
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Early Carboniferous of Victoria, Australia, with 

remarks on the phylogenetic position of the group. 

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Patterson, C. 1964. A review of Mesozoic 

acanthopterygian fishes, with special reference to 

those of the English Chalk. Philosophical 

Transactions of the Royal Society (B) 

247:213-482. 
Paxton, J. R. 1972. Osteology and relationships of the 

lanternfishes (family Myctophidae). Bulletin Los 

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of the Royal Society of Edinburgh 70:337-399. 
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Geest & Portig, K.-G., Leipzig. 
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Greenwood, R. S. Miles, and C. Patterson (eds.). 

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. 1985. An essay on euteleostean classification. 

American Museum Novitates 2827: 1^5. 
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relationships of the paracanthopterygian fishes. 

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Schultze, H.-P., and E. O. Wiley. 1984. The 

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Fossils. Springer Verlag, New York. 
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la Classe des Sciences 43:1-168. 
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|y/|QZ TRANSACTIONS 

LIBRARY OF THE SAN DIEGO 

SOCIETY OF 
JAN 29 1990 NATURAL HISTORY 

HARVARD 
UNIVERSITY 

Volume 21 Number 19 pp. 291-316 15 October 1989 



Ranges of offshore decapod crustaceans in the eastern Pacific Ocean 

Mary K. Wicksten 

Department of Biology, Texas A&M University, College Station, Texas 77843, USA 

Abstract. Distributions of offshore decapods in the eastern Pacific fall into a pattern of at least five 
clusters: the Aleutian Islands to Washington, Washington or Oregon to southern California, Baja California and 
the Gulf of California to central America, Panama or Colombia to Peru, and Chile to Cape Horn. These clusters 
are supported by distributional data at all depths considered, although there is more blurring of provincial 
boundaries at depths greater than 1500 m than at lesser depths. There is a sharp break in faunal distributions 
between that of northern Baja California and all areas to the south, largely due to the replacement of species of 
Pandalus to the north by species of Heterocarpits to the south. The northeastern Pacific is particularly rich in 
species of hippolytid shrimps and lithodid crabs and contains endemic genera of the families Crangonidae and 
Majidae. Species in these and other groups probably underwent extensive radiation in the late Cenozoic and 
dispersed from the northern Pacific into the northern Atlantic and less readily into the southern hemisphere. 
Compared to the northeastern Pacific, the western coast of South America is poor in the total number of species 
and the degree of endemism in decapods. Except for a few cosmopolitan species of the lower continental slopes, 
North and South America have no species in common. 

Introduction 

The coast of the Americas constitutes the longest continuous north-south ocean margin in 
the world. In shallow and intertidal regions, the distributions of co-occuring invertebrate 
species have been used to define at least six zoogeographic provinces. From north to south, 
these are the Aleutian (the Bering Sea to Puget Sound), the Oregonian (Puget Sound to Point 
Conception, California), the Califomian (Point Conception to approximately Bahia Magdalena, 
Baja California, Mexico), the Panamic (Bahia Magdalena to the Gulf of Guayaquil, including 
the Gulf of California), the Peru-Chilean (northern Peru to approximately Isla Chiloe, Chile), 
and the Magellanic (Isla Chiloe to Cape Horn) (Dana 1853, Keen 1937, Ekman 1967, 
Valentine 1966, Briggs 1974). 

Different interpretations have been offered for designations of provinces. For example, 
Brusca and Wallerstein (1979) referred to all of the coastal warm-water (subtropical/tropical) 
area as the Eastern Pacific Zoogeographic Region, noting Briggs' subdivisions of four 
provinces: the Cortez, Mexican, Panamic, and Galapagos. They also recognized the west coast 
of Baja California between Punta Eugenia and Bahia Magdalena as a broad transition zone 
between the Califomian and Cortez provinces. Keen (1937) designated subprovinces of the 
Oregonian province. Garth (1955) considered the fauna of the outer coast of Baja California 
to belong to a province separate from that of the Gulf of California, but Briggs (1974) included 
both faunas in a common province. All of these interpretations were based on species living 
no deeper than the continental shelf. 

There are very few studies of wide-scale distributional patterns of invertebrates of 
offshore areas, at depths of 50 m or more. Menzies et al. ( 1 973) defined offshore provinces by 
depth, sorting invertebrate species into a Shelf Province (about 246 m or less), an 
Archibenthal Zone of transition (to 1000 m), and a deeper Abyssal Province. Their study did 
not consider distributions by latitude. However, Cutler (1975) noted that the region of Cape 
Lookout, North Carolina, constitutes a zoogeographical barrier to sipunculid and 
pogonophoran worms not only of shallow waters, but also to species living on the continental 
slope. Parker (1963) reported the distributions of decapods of the eastern Pacific by latitude. 



292 



but based his work strictly on published literature and made no distinction between species 
living inside the Gulf of California and those on the open Pacific coast. 

Work on moUusks in the eastern Pacific suggests that latitudinal distribution patterns in 
this group change with depth. Reports by Jackson (1974) and Jablonski and Valentine (1981) 
indicate that species living in very shallow water tend to have broader latitudinal distributions 
than those living deeper on the continental shelf, but the trend in decreasing range with 
decreasing depth reverses itself near the shelf-slope break, below which species tend to have 
increasingly wider ranges. The wider latitudinal ranges of species living below the shelf break 
was attributed by Jackson to the damping of environmental fluctuations with greater depth. 
Jablonski and Valentine (1981) noted that western American molluscan provincial boundaries 
are well defined down to 100 m and can be detected across the continental shelf. 

Data for any group of offshore invertebrates in the eastern Pacific are scanty. Decapod 
crustaceans, however, are reasonably well studied, identified, and collected. Being among the 
larger invertebrates, they can be taken with trawls, dredges, traps, and nets, as well as 
identified at times from bottom photographs. Hence, data for this group are more abundant 
than for others. 

Published records of ranges of decapod crustaceans are scattered through expedition 
reports, monographs, systematic papers, and short notes. The earliest major deep-sea 
expedition to visit the eastern Pacific was that of the H.M.S. Challenger, which made 
collections in 1875 off Chile and Juan Fernandez Islands. Bate (1888) reported on many of 
the decapods taken during this trip. The U.S. Fisheries Steamer Albatross collected 
extensively off the Galapagos, Central America, and the coast of the United States from 
southern California to Alaska from 1888 to 1914. Information on decapods taken during its 
cruises can be found in the works of Benedict (1902), Faxon (1895), Rathbun (1904, 1918, 
1925, 1930, and 1937) and Schmitt (1921). 

Only two papers have attempted to describe assemblages of offshore eastern Pacific 
decapods quantitatively by depth. Pereyra and Alton (1972) reported on crustaceans and other 
invertebrates taken by trawls at 91-2103 m and grabs and dredges to 411 m off the Columbia 
River. They provided charts and diagrams of the relative abundance of species at various 
depths and divided the invertebrate groups into an outer sublittoral assemablage (at 91-183 m), 
a bathyal assemblage (at 185-914 m, subdivided into an upper bathyal assemblage at 185^57 
m and a lower bathyal assemblage at 457-914 m), and a bathyal-abyssal assemblage (at 
917-1554 m). Wicksten (1980), using published and unpublished records of decapods taken 
by a variety of methods off southern California, divided the fauna into mainland and insular 
assemblages, providing numbers of specimens and stations per species at depths of 185 m or 
less, 185-923 m, and 923-1846 m. 

Records and ranges of offshore decapods have been presented in works discussing the 
faunas of particular countries, states, or regions. Offshore species of Chile have been reported 
by Baez and Andrade (1979), of the Peru-Chile Trench and its vicinity by Haig (1955, 1974b), 
Garth and Haig (1971), and Garth (1973), of Peru by Mendez (1981), of California and 
western Mexico by Haig and Wicksten (1975) and Wicksten (1980, 1982a, 1987), of Oregon 
by Pereyra and Alton (1972) and McCauley (1972), and of British Columbia by Butler (1980) 
and Hart (1982). Records of species that cross the northern Pacific, ranging from Alaska to the 
Siberian coast, can be found in the work on fauna of the Kurile-Kamchatka Trench by 
Birshtein and Zarenkov ( 1972). 

Ranges of many eastern Pacific decapods are included in wide-scale systematic works and 
short notes. Offshore peneids are discussed by Faxon (1895) and Mendez (1981). Information 
on carideans is included in works by de Man (1920), Holthuis (1971), Crosnier and Forest 
(1973), Wenner (1979). Wicksten (1977, 1978, 1979a,b, 1984), Wicksten and Mendez (1982, 
1983, 1985), and Zarenkov (1976). Records of stenopodids are given by Goy (1980) and 
Wicksten (1982b). Lobster-like decapods are treated in the works of Manning (1970), Firth 
and Pequegnat (1971), Wicksten (1981), and Williams (1986). Anomurans are considered in 
notes and works by Bouvier (1896), Haig (1956, 1968, 1974a,b), Anderson and Cailliet (1974), 
and Ambler (1980). The works by Garth (1958 and 1973) provide information on 
brachyurans. 



293 



Methods 

Large collections of eastern Pacific decapods are maintained at the U.S. National Museum 
of Natural History, California Academy of Sciences. Allan Hancock Foundation (University of 
Southern California and Los Angeles County Museum), and Scripps Institution of 
Oceanography. While identifying and cataloguing specimens from these collections. 1 
analyzed the localities and depths of collection of over 5000 specimens of offshore decapods 
from nearly 500 eastern Pacific stations. Previously unpublished records found while 
examining these collections were published in a short note (Wicksten 1987) as well as in 
previous papers (Wicksten, 1977, 1978, 1979a,b,c, 1980, 1981, 1982a,b, and 1984). I also 
accumulated records of depth distribution and ranges from the published literature. 

For this study, I defined an offshore species as one for which the majority of records of 
occurrence are at 50 m or deeper. I considered only benthic species or those that normally can 
be collected on the bottom despite their limited abilities to swim. (Although the galatheid crab 
Pleiironcodes planipes can be abundant at 23-103 m off western Baja California, [Rowe, 
1985], it was excluded from this study because most of the records in collections and the 
literature did not distinguish between specimens taken on the bottom and those cast ashore or 
swimming in the water column). Species from deep-sea hydrothermal vents and seeps were not 
included. See Jones (1985) for papers discussing the decapod faunas of these areas. 

The area covered by this study is from the westernmost tip of the Aleutian Lslands 
(excluding the Bering Sea) to Cape Horn, including the Galapagos Islands, Juan Fernandez 
Islands, and their immediate surroundings. The area was arbitrarily divided into 5° "squares" 
of latitude and longitude (Figures 1-6), numbered at 1 for the tip of the Aleutians and running 
to 66 at Cape Horn (including offshore banks and nearshore islands), with 67-70 assigned to 
the Galapagos Islands and 71-72 to the Juan Fernandez Islands. The square bounded by 
25-30°N and 1 10-1 15°W (Figure 3) was arbitrarily divided into two parts so that ranges from 
the outer coast of Baja California (28) could be separated from those within the Gulf of 
California (31). Square 8 (Figure 1) is considered to contain only the Pacific side of the 
Alaska Peninsula. 

One hundred eighty-three species of offshore decapods are reported from the eastern 
Pacific (Appendix 1). In this study, endemic subspecies of widespread species {Parapagiints 
pilosimanus henedicti, Pontophilus gracilis occidentalism and Stereomastis sculpta pacifica) are 
treated as eastern Pacific species. Ranges are treated as continuous for all species: if, for 
example, a species is reported only from squares 1 and 10, it is considered to occur also in 
squares 2-9. (No disjunct amphitropical distributions are known for any offshore eastern 
Pacific decapods). All species are included, including those known only from single 
specimens. 

The interested reader can find published records of exact latitude, longitude, and depth of 
occurrence of individual specimens by referring to the works given for each species in 
Appendix 1 . Records of the decapods in the collections of Scripps Institution of Oceanography 
have been published by Luke (1977). The decapods of the Allan Hancock collections have 
been card-catalogued by species and partially by station or collection site, but these data have 
not been published or entered into a computer. Specimens at the California Academy of 
Sciences are being catalogued by species. 

For analysis of co-occurring species, presence-absence data were used. Each species was 
assigned a number, then its occurrence was entered for each 5° square in its range. Initially, I 
experimented with three methods of determining similarity of species composition: simple 
matching, Jaccard's coefficient, and the method of Rogers and Tanimoto (1960). (See Sneath 
and Sokal [ 1973 J for a discussion of similarity coefficients). Of the three methods, only the last 
produced a phenogram that seemed to show distinguishable patterns related to geography. 

Using the method of Rogers and Tanimoto (1960), 1 compared the squares for similarity 
of species composition at five depth ranges: all depths, range number 1 (0-500 m), number 2 
(500-1000 m), number 3 (1000-1500 m), and number 4 (1500 m and deeper). Comparisons 
were done by cluster analysis with the UPGMA (unweighted pair-group analysis) clustering 
algorithm. A phenogram of co-occurrences was produced, with a cophenetic correlation 



294 




Figure 1. Location of 5° X 5° map coordinates across the North Pacific from the Aleutian Islands to the Gulf of 
Alaska. 




Figure 2. Location of 5° X 5° map coordinates along the west coast of North America from Alaska to Baja California 
Norte. 



295 




Nicaragua 



Figure 3. Location of 5° X 5° map coordinates along the west coast of Mexico and Central America. Note that 
numbers 28 and 31 share the same 5° X 5° square. 




Figure 4. Location of 5° X 5° map coordinates from the Isthmus of Panama to central Peru. 



296 




Chile 



Figure 5. Location of 5° X 5° map coordinates from southern Peru to central Chile. 




Cape Horn 

66 






60°- 70» 

Figure 6. Location of 5° x 5° map coordinates from central Chile to Cape Horn. 



297 



coefficient of 0.96. 

Each phenogram shows clusters of squares according to similarities. In comparing the 
clusters with the geography of the coast, north-south patterns appear most consistently at a 
similarity of approximately 0.75. Therefore, the 0.75 level of similarity was chosen arbitrarily 
for discussion of the clusters. 

Results 

Figures 7-11 are phenograms of similarities in species composition by squares. For 
species at all depths taken together, there are seven sets of squares at levels of similarity of 
0.75 or more (Figure 7). From north to south, these include squares 1-18 and 20 (Aleutian 
Islands to Washington), squares 22-25 (Oregon to offshore southern California), squares 27^1 
(Baja California to Isla del Coco), squares 42 and 43 (Gulf of Panama), squares 44^6 and 
48-53 (Colombia to Peru), and squares 54-72 (mostly from Chile) plus the northern squares 
19, 21, and 47. Square 26 (coastal southern California) constitutes a single-member group 
because its similarities to other squares are at levels below 0.75. 

At depth range number 1 (0-500 m), there are seven clusters of squares with a similarity 
of 0.75 or more (Figure 8). The clusters define the following groups by geographic position: 
the westernmost Aleutian Islands, the Aleutians to Washington; Oregon to central California: 
southern California, northern Baja California, and part of the Gulf of California: the southern 
Gulf of California to Peru, and all others. At depth range number 2 (500-1000 m), the squares 
clustered at the 0.75 level follow a similar pattern (Figure 9): Aleutians to Washington, Oregon 
to California, square 26 alone, Baja California to Isla del Coco, Costa Rica to Ecuador. Peru, 
and all others. The patterns for depth ranges 3 and 4 differ slightly: at range 3 (1000-1500 m), 
there are eight clusters (Figure 10), and at range 4 (greater than 1500 m), there are ten (Figure 
1 1 ). Those at range 3 include the following areas: the Aleutians to Washington, Oregon to 
California, square 26 alone, northern Baja California and part of the Gulf of California, 
southern Baja California to Nicaragua, Isla del Coco to Ecuador, Peru, and all others. Those at 
range 4 are from the Aleutians to Washington; offshore of Washington and Oregon; central 
and southern California; southern California, northern Baja California, and the Gulf of 
California; southern Baja California to Nicaragua; square 42 alone; Panama to Peru; Peru to 
Chile; and the rest of Chile with all remaining squares. 

Regardless of the depth range considered, there is a cluster of squares that primarily 
represents the area off southern Chile, the Juan Fernandez Islands, and the Tufts and Cascade 
abyssal plains. These groupings almost surely are an artifact of the use of presence-absence 
data. Examination of the species composition of these squares indicates that they have almost 
nothing in common except for ubiquitous species such as Parapagurus pilosimaiius henedicti. 

In examining distributions at all depths, one finds taxa characteristic of particular regions. 
Table 1 presents examples of endemic species and species reaching either their northern or 
southern limits in particular regions. Refer to Appendix 1 for details of ranges and depth 
distributions of the species. 

Comparisons of patterns of ranges at different depths reveal only slight differences. At 
any depth, there is a sharp break between species that range from northern Baja California 
northward and those that range from there southward. The area from the Aleutians to 
Washington seems to remain distinct in its fauna regardless of depth. At all depths, however, 
patterns of clustering can be seen. 

In comparing distributions of eastern Pacific offshore species with those of shallow water, 
one sees similar north-south changes in species composition. The Aleutian Province seems to 
retain its identity into deeper water. The area from Washington to central California seems to 
contain a mixture of more northerly and southerly ranging species. Square 26 (Point 
Conception to San Quintin Bay, Baja California, hereafter called the Californian Province) is 
distinct at all depths. This area includes marked zoogeographic boundaries for shallow-water 
species: Point Conception is the northern boundary of the Californian Province, while San 
Quintin Bay is the beginning of a region of transition between the temperate Californian 
Province and tropical regions to the south. The fauna of southwestern Baja California and 
much of the Gulf of California either forms a unit of its own or shows similarity to faunas 



298 



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UPGMA clu.ster analysis. Clusters defined at the 0.750 level of similarity. 



303 

Table 1. Characteristic taxa of particular geographic regions. 

Aleutian Islands and Bering Sea to Oregon: 

Endemics: Eiialus hiiinguis, E. piisloliis, /■.. siicklcyi. E. townsencli, Heptcnarpus nioseri, Pandalopsis dispar, PaiuUihis 
goniiiriis, P. hypsinotiis. P. stcnolcpis. P. tridetts. Argis ovifer. Pugunts confiagosus, P. cornulu.s, Lithodes 
aequispinci. Chirosryliis sp., Miinidopsis hcringana, Hyas lyratiis. 

Northern range limits: Axiopsis spiiuilicuuda, Cahistacus stillrostris, Callicinassu goniophthalma, Eiiulus haihatus, E. 
macrophthulmus. Heptacarpus fle.xus. Lehheiis washingtonianits, Spirontocaris holmesi, S. sica, Pandalopsis 
ampla, Paiiduhis jordani, P. platyccros. Mctacrangon varlahilis. Pugiirislcs mrgidiis. Pugiirtts caplllalus. P 
taiiiwri, Lopholithodes foraminatus, Paralomis miilti spina, Mitnida c/uadrispina. Miinidopsis c/iiadrala, M. scahra. 
M. verrilli, M. verrucosus, Chorilia I. longipes, C. longipes turgida. 

Southern range limits: Pandalus horealis, Pagurus aleiiticus, Chionoecetes angulalus angidaius. C. hairdi, Oregonia 
bifurca. (Species ranging into northwestern Pacific). 

Central-Southern California, Northern Baja California: 

Endemics: Argis californiensis. Crangon lomac. Paralithodes californiensis, P. rathhuni. Cliirostyliis pcrarmatus. 
Upogehia lepta. 

Northern range limits: Benthesicymus altus, B. tanneri, Stereomastis sculpta pacifica, Pontophilus gracilis 
occidentalis. Glyphocrangon spinulosa, G. vicaria, Parapagurus liaigae, Glyplolitliodes cristaiipes, Gulathea 
californiensis, Munida hispida, M. depressa, M. diomedeae, Munidopsis hystrix. 

Southern range limits: Callianassa goniophthalma, Eualus barhatus, Lebbeus washingtonianus, Spirontocaris 
holmesi, S. sica, Pandalus jordani, P. platyceros, P. tridens, Crangon abyssorum, Metacrangon variabilis, Pagurus 
caplllalus, P. tanneri. Paguristes turgidus, Lithodes couesi, Lopholithodes foraminatus, Paralomis multispina. P. 
verrilli, Munida quadrispina, Munidopsis aspera, M. verrilli, Chionoecetes tanneri. Chorilia longipes, C. longipes 
turgida. 

West Coast of Baja California, Gulf of California: 

Endemics: Processa pippinae, Munida perlata. 

Northern range limits: Plesionika heehei, Heterocarpus vicarius, Metacrangon procax, Nephropsis occidentalis. 
Upogebia jonesi, Paralomis papillata. Munidopsis hamata. 

Southern range limits: Calocaris quinc/ueseriatus, Lebbeus vicinus montereyensis, Pandalopsis ampla, Galathea 
californiensis. 

Southwestern Mexico: 

Endemic: Heptacarpus yaldwyni. 

Northern range limits: Nematocarcinus agassizii, Heterocarpus affinis, Paracrangon areolata, Sclerocrangon atrox, 
Glyphocrangon alata, Munida refulgens, Ethusinafaxonii, Trachycarcinus corallinus. 

Southern range limits: Munidopsis depressa, M. quadrata;. 

Gulf of Panama: 

Endemics: Glyphocrangon sicaria, Uroptychus nitidus occidentalis. Munida gracilipes, Munidopsis agassizi. M. 
crinita. M. hendersoniana. M. sericea, M. tanneri. Ethusa ciliatifrons, Cympolia tuberculata. 

Northern range limits: Polychelcs tanneri. Heterocarpus hostilis. Lithodes panatnensis. Lopholithodes diomedeae, 
Paralomis aspera, P. longipes, Munida propinqua. Munidopsis villosa. 

Southern range limits: Upogebia jonesi, Parapagurus haigae, Munidopsis hamata. 

Galapagos: 

Endemics: Spongicoloides galapagensis, Chirostylus defensus, Uroptychus granulatus, Munidopsis margarita. M. 
ornata, Rochinia cornuta, Rochinia occidentalis. 

Northern range limit: Glyphocrangon loricata. 

Southern range limits: Benthesicymus altus, Polychelcs tanneri. Glyphocrangon vicariu. Munida hispuhi. Munidopsis 
rostrata. 

Peru: 

Endemics: Bathypalaemonella delsolari. Lebbeus carinatus, L. curvirostris. L. splendidus. Pagurus imarpe. Lithodes 
wiracocha, Paralomis inca, Cymonomus menziesi. Honu)lodromia robertsi. Acanthocarpus delsolari, Trizocarciniis 
peruvianus. 

Northern range limit: Lophorochinia parabranchia. 



304 

Southern range limits: Calastacus stilirosfris, Nematocarcinus agassizii, Heterocarpiis affinis, H. Iiosfilis, H. vicariiis, 
Plesionika beebei, P. trispinus. Metacrangon procax, Paracrangon areolata, Sclerocrangon atrox. Glyphocrangon 
loricata, Pwbeebei mirabilis, Lithodes panamensis, Lopholithodes diomedeae, Paralomis aspera, P. longipes, P. 
papillata, Munida propinqua. Munidopsis hystrix, M. scabra. Ethusina faxonii, Trachycarciniis coralliiuis. 

Southern Peru to Chile: 

Endemics: Nematocarcinus pwximatus, Leontocaris pacificus, Heterocarpiis reedi. Polycheles chilensis. Willemoesia 
challengeri, W. pacifica. Lebbeus scrippsi, Pagiirus delsolari. Trachycarciniis hystricosus. 

Northern range limit: Pagiirits forceps. 

Southern range limits: Benthesicymus tanneri. Nephropsis occidentalis. Stereomastis sciilpta pacifica, Pontophilus 
gracilis occidentalis. Glyphocrangon alata, Glyptolithodes crislatipes. Munidopsis dioniedae, M. verrucosus. M. 
villosa, Lophorochinia parahranchia. 

Southern Chile to Cape Horn: 

Endemics: Campylonotus semistriatus, Steromastis suhmi. Neolithodes diomedeae. Chirostylus niilneedwardsi, 
Munida curvipes. Munidopsis opalescens. M. trifida. 

Southern range limits: Haliporoides diomedeae, Pagurus forceps, Munidopsis aspera. 



farther south. From western Mexico to Peru, species appear to have greater latitudinal range in 
shallow water than in deeper water. The fauna of the Galapagos Islands does not appear 
distinct from that of the coast of tropical western America, but this may be an artifact of 
limited sampling: Munidopsis margarita and M. ornata, for example, are known only from 
specimens taken by the Albatross in 1891 (Faxon 1895). 

Two genera of spot prawns (family Pandalidae) show allopatric distributions in the eastern 
Pacific. In the northeastern Pacific, species of the shrimp Pandalus range from Alaska to 
northern Baja California. From the Gulf of California south to Chile, species of Heterocarpus 
are found. Both are relatively large epibenthic shrimp of sand, mud, or gravel bottoms. Being 
easily recognized to genus and of commercial importance, these shrimp have been studied 
better than have many other decapods. The allopatric distributional pattern, therefore, is not 
likely to be an artifact of sampling or data analysis. 

Only 25 decapod species have been reported exclusively from 1500 m or deeper in the 
eastern Pacific (Table 2). Of the species living at depths of 500 m or deeper, 18 are 
widespread: the hermit crab Parapagunis pilosimanus heneclicti seems to be ubiquitous at its 
depth range (414-2200 m), being reported from the Kurile Islands south to the Juan Fernandez 
Islands (Birshtein and Zarenkov 1972, Haig 1955). Pontophilus gracilis occidentalis, 
Benthesicymus tanneri, Stereomastis sculpta pacifica, and Glyptolithodes cristatipes range 
from southern California to Chile (Wicksten 1976. 1979b, 1982, Mendez 1981). 
Glyphocrangon vicaria ranges from southern California to the Galapagos; G. spinulosa, from 
southern California to the Gulf of Panama (Wicksten 1979a). Benthesicymus altus is 
widespread in the Atlantic and Pacific (Schmitt 1921). Pandalopsis ampla ranges in the 
eastern Pacific from Washington state to the Gulf of California (Schmitt 1921, Wicksten 1987), 
but also has been reported in the southern Atlantic off Argentina and Uruguay (Takeda and 
Hatanaka 1984). Takeda and Hatanaka (1984) suspected that the Atlantic and Pacific 
populations may in fact be separate species. Munidopsis latirostris and Axius acutifrons range 
from the eastern Pacific into the Indo-West Pacific, while Munidopsis hairdii, M. ciliata, M. 
suhsquamosa, Stereomastis nana, Nematocarcinus ensifer, Parapagurus ahyssorum and 
Ethusina rohusta are reported to be cosmopolitan at their respective depth ranges (Faxon 1895, 
Firth and Pequegnat 1971, Ambler 1980). 

Discussion 

In interpreting patterns of ranges of offshore decapods, one should bear in mind the 
limitations of the data base. Data for many groups of offshore crustaceans are frustratingly 
sparse. Sixty of the species here analyzed are known from five or fewer specimens, many 
collected only once at the type locality. Species living on hard bottoms, such as members of 
the families Stenopodidae and Chirostylidae. are difficult to collect. Other seemingly 



305 



Table 2. Species found at 1500 m and deeper. 



Polyvhcles chilcnsis Sund: 2500 m. 
Stereonuistis nana (Smith): 1544-2412 ni. 
Willemoesia challengeri Sund: 2520-4000 m. 
Wlllemocsia pacifica Sund: 2520 m. 
Ncmatcicairiinis pro.xinuitus Bate: 2516-2654 m. 
Lchheits carinatiis Zarenkov: 1850 m. 
Lehheiis ctirvirostris Zarenkov: 1680-1860 m. 
Pontophihis i^racill.s occidentalis Faxon: 1789^082 m. 
Glyphocrangon rimapes Bate: 2500 m. 
Neolithodes diomedcac (Benedict): 1923-2478 m. 
Munidu ciirvipcs Benedict: 1924 m. 
Miinida pciiata Benedict: 1920-3292 m. 
Mnnldnpsis antoni (Milne Edwards): 2519-3676 m. 
Miinidopsis aries (Milne Edwards): 2912-3025 m. 
Miinidopsis heringana Benedict: 2800-3276 m. 
Miinidopsis cascadia Ambler: 2743-2926 m. 
Miinidopsis ciliala Wood-Mason: 2030-2875 m. 
Miinidopsis hendersoniana Faxon: 1869 m. 
Miinidopsis lostrata (Milne Edwards): 2153-2492 m. 
Miinidopsis tiiftsi Ambler: 3500-3858 m. 
Miinidopsis verrucosus Khodkina: 3932—4880 m. 
Miinidopsis vicina Faxon: 3063-3885 m. 
Miinidopsis yaquinensis Ambler: llb'i-lZll m. 
Etinisinafa.xonii Rathbun: 2999^081 m. 
Ethusina rohusta (Miers): 1618-3334 m. 



widespread families, such as the armored shrimps CGlyphocrangonidae) and blind lobsters 
(Polychelidae) live only on the lower slope at depths (1000 m or more) that have not been 
sampled in many areas. (There are no published reports of either family, for example, north of 
Point Conception, yet both probably occur along the northern Pacific slope — related species 
so occur in the North Atlantic and off northern Japan). Many species from off Central 
America, the Galapagos, and the Juan Fernandez Islands are known only from the collections 
of the Albatross and ChaUeni>ei\ not having been collected since then. It can be difficult to 
judge from only a few records whether or not an offshore species has a continuous or 
discontinuous distribution. (The lack of any amphitropical distributions among deeper 
decapods, for example, may be an artifact of sampling.) However, data for commercial species, 
such as species of Pandalus, are more abundant than for other decapods and may bias the 
analysis. Records may be misleadingly abundant in well-studied areas such as the Californian 
Province, where the University of California, Santa Barbara, the University of Southern 
California, and Scripps Institution of Oceanography are studying the benthic fauna. 

If deeper waters contain a more homogeneous environment than those of the continental 
shelf, why can one see clusters of squares by latitude at all depth ranges? Topographic barriers, 
such as the trenches off Central America, Peru, and Chile and the basins and ridges of 
southern California may limit some benthic species, while subsurface regimes of temperature, 
salinity, and oxygen may limit others. Biological factors, either current or past, may be 
involved — little is known about dispersal abilities, predator-prey relationships, or competitive 
interactions of offshore decapods. 

The abundance of lithodid crabs and hippolytid shrimps in the northeastern Pacific 
suggests that there has been evolutionary radiation of species in the area. Ekman (1967) 
speculated that elements of the North Atlantic fauna were derived from the North Pacific 
through "temporary and difficult communication." Menzies ct al. (1973) accounted for 
amphiboreal distributions by dispersal of species during a Pliocene trans-Arctic sea connection 
between the Pacific and Atlantic. During this connection, groups previously endemic to the 
Pacific colonized the Atlantic. Colonization ended during the unstable glacial conditions of 
the Pleistocene. Such a faunal exchange across the Arctic enabled species of certain genera 
(such as Spirontocaris) to colonize the Atlantic, while others (such as species of Heptacarpus) 



306 



were unable to cross the "filter bridge." 

Ekman (1967) noted the abundance of cold-water caridean shrimps of the family 
Hippolytidae in the northern Pacific, referring to these shrimps as various species of 
Spirontocaris. Holthuis (1947) split the genus into four genera, Spirontocaris sensu stricto, 
Heptacarpus, Eualus, and Lebbeus. Ekman's observation still has merit — species of 
Spirontocaris are far more abundant in the northern Pacific than in the northern Atlantic, the 
only other place where they occur. Species of Heptacarpus are confined to the northern 
Pacific, from Japan across the Aleutians to off Oaxaca, southern Mexico. More species of 
Eualus and Lebbeus are known from the northern Pacific than from anywhere else, although 
species of each occur off western South America and elsewhere; species of Lebbeus also occur 
at bathyal depths in the Indo-Pacific, the Arctic, and boreal Atlantic, while species of Eualus 
live off Europe and South Africa (Holthuis 1947, Noel 1978, Wicksten 1979c, 1984, Mendez 
1981, Wicksten and Mendez 1982). 

A cladistic analysis of the Hippolytidae by Christoffersen (1987) indicates that members 
of Lebbeus, Heptacarpus, Spirontocaris, Eualus, and the mostly tropical genera Thor, 
Thoralus, and Birulia are closely related and perhaps should be split off from the old family 
Hippolytidae into a new family, the Thoridae. Distributional patterns of these genera suggest 
origin and radiation in the Pacific with subsequent spread into the Atlantic. The patterns of 
distribution of the four cold-water genera resemble that of the rock crabs, genus Cancer, which 
are most abundant in the Pacific but also occur across the northern Atlantic Ocean. The 
patterns differ, however, in the lack of any records of the four hippolytid genera from Australia 
and New Zealand, where one species of Cancer occurs. Fossils of Cancer spp. suggest that 
these crabs originated at latest in the Miocene in the northern Pacific and dispersed from there, 
following cold-water regimes, in the Pliocene and Pleistocene (Nations 1975). Although there 
are no fossils to provide evidence of past distributions of the hippolytids, at least the four cold- 
water genera seem to follow much the same pattern as the species of Cancer. 

Bouvier (1896) noted that there are many species of the king crab family (Lithodidae) in 
the northern Pacific: there are more in the area from the Aleutian Islands to northwestern Baja 
California, from the intertidal zone to bathyal depths, than elsewhere. Of those found 
elsewhere, species of Lithodes and Paralomis live offshore in both the northern and southern 
hemispheres. Glyptolithodes cristatipes ranges from Chile to southern California. 

In two other decapod families there are genera endemic to offshore waters of the northern 
hemisphere. Among the bay shrimps (family Crangonidae), the genera Argis, Crangon, and 
Metacrangon live in the North Atlantic and Pacific. Of the spider crabs (Majidae). species of 
Chionecetes and Hyas live in the North Atlantic and Pacific, while species of Chorilia and 
Oregonia are found only in the northern Pacific. One majid genus, Lophorochinia, seems to be 
endemic to the Peru-Chile Trench (Garth and Haig 1971). 

Decapods are not the only organisms showing relatively high diversity of species or 
endemism of genera in the northern Pacific. The west coast of North America is second only 
to Australia and New Zealand in numbers of unique algal species and is noted for such large 
endemic genera of brown algae as Nereocystis and Postelsia (Abbott and Hollenberg 1976). 
Estes and Steinberg (1987) hypothesized that the larger algae of the order Laminariales 
radiated in the northern Pacific following the onset of late Cenozoic polar cooling. These 
characteristic cold-water plants are not found in tropical regions and cannot tolerate warm 
ocean water. Evidence from molluscan fossils and other material suggests that the polar 
cooling trend could have begun in the middle to late Miocene, allowing spreading of cold- 
water groups. The kelps apparently spread across the northern hemisphere into the Atlantic, 
then later colonized the southern hemisphere after closure of the Panamic seaway halted the 
westward flow of warm water from the Caribbean region into the eastern Pacific. Kelps may 
have spread into the southern hemisphere as late as the Pleistocene, when glacial periods 
narrowed the distance between cold-water regions of the northern and southern hemispheres. 
Northern Pacific decapods may have followed a similar pattern of diversification and dispersal, 
but could have spread more easily than algae because of their ability to survive in cold water 
at greater depths. Kelps require sunlight for photosynthesis and cannot survive at depths of 50 
m or more. Decapods may have spread by equatorial submergence — remaining in the same 



307 



temperature regimes in the tropics as in temperate regions by moving into deeper water. 

The northern Pacific contains many other examples of species-rich cold-water groups. Of 
the living species of chitons (MoUusca: Polyplacophora), more can be found along the 
northwestern coast of North America than on any other coast of comparable length in the 
world. Conspicuous species such as Cryptochiton stellerl and Katherina tunicata have wide 
ranges in the northern Pacific (Haderlie and Abbott 1980). Two families of fishes, the 
Embiotocidae and Hexagrammidae. are found only in the northern Pacific, from Japan to 
western Mexico, while species of the families Stichaeidae and Cottidae as well as of Ihc genus 
Sehastodes (family Scorpaenidae), although also occuring in the northern Atlantic, are by far 
more diverse in the northern Pacific (Herald 1961). 

Except for the examples given in the families Pandalidae, Hippolytidae, Crangonidae, 
Lithodidae, and Majidae, offshore decapods of the eastern Pacific belong to widespread genera 
found at characteristic depths or temperatures. Menzies ct al. (1973) refer to these widespread 
groups as the Tethyan fauna, implying that their distributions could be related to the Tethyan 
Seaway of tropical regions in the early Mesozoic. Latitudinal ranges of the species vary from 
extensive to seemingly small, but the paucity of data for many groups makes family-by-family 
comparison of ranges difficult. 

Manning and Reaka (1987) related differences in rates of evolutionary change of 
stomatopod crustaceans to differences in larval dispersal ability, habitat, and body size in 
different lineages. Evolutionary changes in stomatopods generally are inversely related to the 
size of the postlarvae. Lineages of small body size seem to have the most rapid rates of 
evolutionary change. The degree of species endemism is associated with substrate type, 
speciation being seemingly more common for species inhabiting coarse rather than level 
bottom habitats. Larger species of temperate habitats tend to have broad ranges: for example, 
Hemisquilla ensigera can be found in California, Chile, New Zealand, and Australia. 

Because of the scarcity of information on the distributions, habitats, and life histories of 
offshore decapods, it is difficult to compare their evolutionary rates to those of stomatopods. 
Stomatopods are rare in cold deep water, being represented by only a few species. As a 
general rule, small decapods seem to be more common and diverse in shallow rather than deep 
waters: most offshore decapods measure at least 1 cm in largest dimension. Decapods of 
deeper hard substrates are rarely collected, so the degree of species endemism among them is 
difficult to determine. 

It is interesting that among eastern Pacific decapods living at 50-1500 m. there are no 
examples of strictly amphitropical (occurring in both northern and southern temperate regions 
but not in the tropics) genera or species. Some of the typically cold-water families and genera 
live at greater depths in tropical regions than in temperate and boreal areas — species of 
Lehheus, for example, can be found almost in the intertidal zone in California, but tropical 
representatives of the genus are found on the continental slopes or deeper. 

The fauna of western South America has fewer species and genera of decapods than does 
North America and has only one reported offshore endemic genus (Lophorochinia). While 
many of the species found from Peru south to Chile are endemic to the area, they belong to 
genera with widespread distributions. 

The relative paucity of offshore decapods off western South America, in both numbers of 
species and degree of species endemism, is difficult to explain. The coast is geologically 
active, but so is that of western North and Central America. It is possible that gradual cooling 
of the coastal waters since the Mesozoic eliminated many elements of the fauna over time: 
Menzies et al. (1973) noted that cooling, which extended from the Mesozoic until glaciation in 
the Miocene, resulted in a progressive loss of invertebrate groups from the Antarctic. Tropical 
waters to the north may have inhibited colonization by the common cold-water families of the 
northeastern Pacific. Members of genera that inhabit bathyal zones (such as Lehheus and 
Lithodes) seem more likely to co-occur in the northern and southern Pacific than do groups that 
live in shallower areas. The slope region off Peru and Chile, however, contains extensive areas 
of low oxygen concentrations, inhabited by bacterial mats and not by larger invertebrates 
(Rowe and Haedrich 1979). Perhaps a combination of historical elimination or decrease in 
faunal diversity and modem conditions that inhibit decapod life has resulted in the paucity of 



308 



species in this area relative to the coast of North America. 

Between the fauna of the eastern Pacific and that of other offshore regions there are 
puzzling differences. The northern Pacific is rich in cold-water caridean shrimps of the 
families Pandalidae and Hippolytidae. Crabs of the family Lithodidae are more diverse than in 
other areas. However, the abundant red crabs, Geryon spp., found on the slopes of the Atlantic 
and Indo-West Pacific region, are entirely absent, while members of the family Goneplacidae, 
widespread in the warmer parts of the Atlantic, seem to be relatively uncommon on eastern 
Pacific slopes. No species of antlered crabs, family Latreilliidae, have been reported from the 
eastern Pacific, although they occur in the Atlantic, Indo-West Pacific, and Mediterranean. 
Giant isopods {Bathynomus spp.), conspicuous inhabitants of the continental slopes of the 
tropical western Atlantic and Indo-Pacific regions, also are absent from the eastern Pacific. 

Reaka and Manning (1987) noted gaps in the distributions of otherwise worldwide groups 
of stomatopods. For example, the species of Alima, are found in tropical waters worldwide 
except in the eastern Pacific. They speculated that such groups have undergone extinction. 
Such apparent extinctions in stomatopods have been more numerous in the eastern Pacific than 
in the western Atlantic. Perhaps such local extinctions have occurred in decapods as well as 
stomatopods. 

The sharp break seen at all depths between the fauna of southern California and northern 
Baja California combined and all areas to the south is due largely to the allopatry of Paudalus 
and Heterocarpus. Changes in the species composition within the family Hippolytidae also 
contribute to the break. 

Systematic treatments of eastern Pacific decapods for the most part have considered 
intertidal and shallow-water species, not animals living at depths of 50 m or more. Much of 
the information on offshore species consists of basic descriptions and accounts of where 
specimens were collected without comparison of records of related species. More analysis of 
the evolutionary relationships of the taxa might shed light on the historical biogeography of the 
eastern Pacific. 

Acknowledgments 

I thank Janet Haig, Allan Hancock Foundation, Spencer Luke, Scripps Institution of 
Oceanography, and Dustin Chivers and Robert van Syoc, California Academy of Sciences, for 
their assistance in finding records of species, and Steve Taylor, Russ Souchek, and Terrence 
Walters, Texas A&M University, for help with the analysis of data. Richard Brusca, San Diego 
Natural History Museum, and Gilbert Rowe, Texas A&M University, provided valuable 
criticism of early drafts. 

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